You're assuming that they're stationary, and not moving around. Even if this is them now, there's no guarantee they'll be in the area next year, or even next month.
They are likely to be stationary. This is the área their hall was and if they bothered to erase its location from everyone's minds there is Little point to keep moving around.
They are wielding magic powerful enough to unilaterally erase the memories of an entire planet. They are in possession of the one and only space ship on the planet. At least a few of them must know Instant Transmission, which has an interstellar range if you know where you're going. They must have spent the years preparing some sort of contingency plan which it would probably be very bad to trigger. We don't even know if what we're picking up is the Senzu at all, which means we might set them off without gaining any information about them, or even awaken something worse. At the very least, it may well tell others that we are looking for them or lead them to the Senzu, and we probably don't want anybody else to know just yet.
If pinging were a good idea we would have just spend this whole time grid-searching with active kidar. I'm sure that lots of other people already have.
There are a few things you are failing to consider, I think:
As the year spins towards its end, you find yourself flying through the clouds, panning out across the land with your senses. You're looking for House Senzu.
You've been looking all year, but they've hid really well. Despite a year's searching, you haven't found a trace of them. Their Sorcerer must be really talented.
You're just about to give up when you...do you feel something?
You're combing through the continent that Senzu Hall is know to be located in, even if their wards have erased their exact location from everybody's minds. You've been doing this, usually staying above the clouds to stay out of sight, about once a month at irregular intervals. And as always, your ki is suppressed.
And for the first time since you started, you think you feel something. Right...
...no, it's gone. You grumble in annoyance. That leaves you in a pickle. You could just keep listening, but if you really wanted to, you could send out a pulse of ki and listen to the "echoes." Like sonar, that's one way of gaining a lot of detail very quickly. If they are suppressing imperfectly -- if they're expressing any power at all -- you'll find them. But like sonar, active pings for ki sense are a lot more conspicuous. They'll know you've found them, if they're out there.
You hover in place for a moment, torn by indecision.
We are using our ki sense to look for them. Considering that there are ki supression wards on individual homes, it is unlikely that we sensed a "normal" amount of power level, or we wouldn't have sensed them at all, which means they re probably training right now and we would have to wait for a similar time to sense them again. Now, usually a subtler approach is recommended but if we wait for next turn then they would have had two years to prepare and would have gathered momentum motivation wise to move against the clans. We should have gone looking for them in the first turn in my opinión and giving them more time to do whatever they are planning is more likely to bite us in the tail.
In later posts you express concern about these guys being the Senzu. If they aren't then we should be able to sense them easily given our skills which makes it concerning that we can't and is even more reason to investigate. If they are the Senzu then it is unlikely to be a decoy since they would have to have put several ki supression wards and set on them a spell to fake a ki signature in order to catch the attention of Random Saiyan Number 1 who is looking for them with no way to know if they would actually be worth the effort of setting a trap for. Furthermore, if we do find them then we can IT there or fly there before they can flee since, even if some probably know IT it is unlikely the whole clan can escape with it. So you either get them to make a stand or some of them flee. If the first then we can talk to them using both our talented level communication and all the traits that boost it; if they have some sorcery contingency against super saiyans then they either would have used it already or they are working on it, in which case giving them more time to perfect it would be a bad idea. If some try to flee (which is a bad idea since it would allow other saiyans to sense them since you can't IT to some place you can't locate with ki senses and there is no inhabited system close enough for them to sense and go off world) then the fact that we would not move against those who can't should help convince them we come in peace.
While they saw the extermination of House Talt and they would be naturally wary of retaliation, that will not change in a year and th further they continue this rebellion the more likely they are to end like them. The only ways you could convince them that there is no way for us to turn them in are two; for us to openly move against Lady Vegeta and oppose the sealing (which I don't think we were planning to do next year and for which we were planning to convince the Senzu sorcerer to help us with first in case we couldn't convince Dandeer to do it first) or to approach them slowly enough that they see we won't sell them in but which would require for them to notice us first, which could also set them off into fleeing.
Finally, there is the fact of the likeness of success:
[ ] Send out an active ping. You can chase them down if you need to. Opposed check of your Ki Sense vs. their Ki Control with a massive bonus for you, strict pass/fail results. They know that you're looking either way.
[ ] Keep listening with passive senses. Opposed check with no bonus and possible distance penalties depending on where they are, but they won't know you're looking.
So, the way I see it your argument is that even if we fail, since they won't know we are looking we could try again next year without them putting additional safeties. It is an aproach of getting more chances to try, maybe even get a slight bonus since we know aproximately which part of the continent to search. However, the longer we take to resolve this the worse the situation with Senzu will getit will likely be harder to convince them we come in peace the longer we take (unless we reveal the truth of the sealing before that), we might get a penalti to sense them due to distance and the ping is far more likely to find them now since not only are we Exceptional at sensing but we would get a
massive bonus to finding them.
All in all, I think that the advantages of finding them now outweight the ones of waiting, that the chances of finding them now a good enough to do so and that the propposed risks are, if anything, going to get worse if we wait. Thus:
[x] Send out an active ping. You can chase them down if you need to. Opposed check of your Ki Sense vs. their Ki Control with a massive bonus for you, strict pass/fail results. They know that you're looking either way.
[x] Things that are.
Things that will be would also be useful to detect future thrats but there are so many players we already know that anything we learn about them would be helpful to decide how to deal with them, without spending actions to find out about it.
