Okay, just to throw a few more monkey wrenches into the works:
First of all, I will point out that, in most of the universes or systems that I've seen, technology
is its own special snowflake, and exists in a manner that is distinct and separate from magic. Mage the Ascension is one of the few exceptions I've ever seen to this rule, because in that particular setting, magic and technology
are one and the same. But in almost every other setting I've seen, technology is something that is based upon a totally different set of principles, and a different paradigm, from magic.
Secondly, mathematics and technology are two
totally separate entities. Just because technology can be fooled by a spell, doesn't mean that math can...which means that, sooner or later, you still run into the same problem. Unless magic exists as its own totally independent universe, ala Harry Potter, you start running into the problem that non-magical people can and will get caught in it...and that means that sooner or later, you run into those good old statistical anomalies. Even changing records won't help with this, not unless you can slightly change every record across the planet. Sooner or later, you run into the bean conundrum all over again, because the numbers don't add up, and there is no scientific explanation as to why. In order for the Masquerade to work, magical beings would have to be very rare, very widely scattered, fully aware of each other, in constant contact,
and their effects would have to be so subtle and minor that they disappeared into the admittedly vast amount of stuff that we don't know about yet.
Even then, the pressures we're talking about, from the outside, with scientists just trying to explain anomalies that, according to what they know, can't exist, but still do? Those are just the passive pressures on the Masquerade, which would be considerable. Active pressures, from young idiots who think that their magic makes them special? Whole different ball game. In a world where magic can directly interact with what humans consider to be the real world, all it would take would be one mistake made at the wrong time to leave a muggle very much convinced that that guy with the beard and the stick just threw a fireball at somebody else. Maybe the guy's drunk, maybe he's higher than a kite, maybe he's just not too sure of his grip on reality, or maybe he just doesn't know enough to be able to come up with a convincing explanation for why what he saw is possible without magic. None of that matters. What matters is that the guy now believes that magic is possible, and when he looks around, he realizes that magic is a better explanation for other things he's seen.
Even if he hasn't seen anythign else in his life that is magical, this belief will still persist, and the witness will still start attributing other things to magic, simply because he doesn't understand them.
The purpose of the Masquerade is to find these witnesses, and shut them up, to track down the young idiots who are flaunting their powers, and get them to behave, to...well, you get the idea. In short, the Masquerade is something to be concerned with, to maintain, if and only if the people around you are capable of grasping that magic exists. If there is no possible evidence that something unnatural happened, if scientists can't even tell that something is off, than there is no Masquerade...and, sooner or later, there is no magic, either.
And, again, I will remind you that scientists have studied some really, really, really stupid crap over the years. The psychic powers of rats are only the beginning. If you want more examples, check out this article:
Dumb science.
Scientists will study darned near anything, if they can get the funding, for the simple reason that, sometimes, dumb science turns out to not be dumb (there's an example of that on item 8 on the list I linked, by the way). So...yeah. Mundane explanations or not, sooner or later, somebody would take a long, hard look at whether or not magic existed, just because what the hell, maybe it does. And, unless you had
people actively blocking such research, that scientist would eventually start digging out evidence that only magic would logically explain, for the simple reason that his or her funding would depend on finding some kind of results. My brother works in the science industry, and he tells me that this is
exactly how it works. Even a
lack of evidence that there is anything to research will trigger additional research, because such a result is so damned unusual that it counts as a weird anomaly in and of itself. It's sort of like meeting a truly honest politician, or riding a unicorn--it's so weird that you just have to stop, and say WTF?
All of this is really sort of beside the point, however. Something like the Masquerade is
not required for a good urban fantasy--many authors, shows, and other sources portray quite effective urban fantasies in worlds where magic is openly acknowledged to exist. Hellboy effectively becomes a world like this, as does the Underworld series. Most comic book series
run on something like this, as does the Ghostbusters series, and the Sookie Stackhouse mysteries. Kim Harrison's works seem to run on this, as do at least some of the works of Patricia Briggs. There are many others that do the same thing. If your thing to induce tension is to try to maintain the Masquerade, cool. But be aware that you only get to fiat so many aspects of the world you're creating, before the audience starts demanding plausible explanations. If you want them to accept the existence of the Masquerade, you'll need to pay a great deal more attention to other aspects of the universe.
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