...Enough of the saiyans you're talking to will have telepathy that the backtalk would still be devastating if you sent a one-to-thousands telepathic advertisement.
Hmm... I'm wondering how many non-Exile Garenhulders there are? The Exile population is 300,000. Looking at RL growth rates, and being a bit conservative, I'm going to guess 3 billion Garenhulders. That's 1 in 10,000.
Assuming 1 in 5 Exiles know Telepathy, that means that out of a random population of 50,000, the telepath would expect only 1 reply.
Of course, Saiyans tend to live close to each other, so by avoid those areas, the odds of contacting a Exile that way decreases by, say, 90%? I believe only like half of the Exiles live amongst humans?
So, as long they only contact people outside of the major Exile concentrations, that'd be 3,000 responses, in exchange for hitting most of the Garenhulders. Split the task up so you only hit 1,000,000 at a time, and you'll contact an average of 1 who could reply Exile each time.
...And I just realised I've spent the last 25 minutes on this due a stray thought.
The former. He's yet to in any incarnation of the show, I don't see why he should change his behavior in the future. (If he in fact does at some point in the future, then bully for him, and that's the day this quest goes full-AU, because that's too big a retcon to swallow.)
If he does, it'd most likely be to Uub.
Of course, the Kaio-ken and Spirit Bomb were both King Kai's techniques, and Instant Transmission belongs to the Yardrat, so he might not have taught them out of respect or some such?
Or, you know,
no one asked.