I'm a researcher at a face recognition company. Big sunglasses do a good job.

That's fantastic news! I wear those terribly unfashionable goggle-like sunglasses for old people that go over my prescription glasses. Looks like I'm safe for the near future. :)

I wish it were that easy. By law you have to be identifiable in public, therefore you can't wear a mask that covers completely your face.

Which law is that?

Plastic surgery will become more popular too.

The the state of Georgia there is just such a law:

http://www.lawskills.com/code/ga/16/11/38/

Interestingly, this occasionally sparks trouble with the police at geek/nerd conventions where costuming is popular.

Highly doubtful. I'd know a lot of dead snowmobilers.