I live in S. FL and I am convinced that it’s not uncommon for snowbirds to vote here AND in NY or NJ.
I've heard that for years and I don't doubt that some "double voting" happens as you point out. Of course, a photo ID wouldn't address that issue (would it?).
However, I think I would favor a periodic computer matching of voter rolls between, say, Florida and New York followed by a process of weeding out duplicates (and possibly prosecution of those found to have committed election fraud by illegally voting in one state or the other).
I’m sorry, as usual I wasn’t really clear. The problem is that when they catch them they just don’t really do much to them. I think it’s a felony, but they tend to just let them go. I think if they threw the book at a few of them (and actually tried to find them, which with computers these days is probably not difficult) and made it pretty public, it would probably cut it way down.
And if you ever get caught and convicted of voter fraud I don’t think you should ever be allowed to vote again.