[BobaFloutist]

I don't even know that it's explicitly illegal. Google maps is allowed to warn you about speed traps.

[mindcrime]

I agree, it probably isn't really explicitly illegal. But if one put together such a thing, depending on how they decided to use it, I have a hunch that the State would find something to charge them with. I'll resist the temptation to say more, to avoid going too overtly political here.

[gloyoyo]

I'm pretty sure it's not outside of the range of ANYONE to whip up in a fortnight, and have distributed near instantaneously.

If anything, it's the most basic of "wireless site survey" applications.