I remember when i was younger, i used the 3d glasses the came with one of my transformers video, and played alot of games wearing them, i distinctly remember playing Sonic and Knuckles with them. I had 3d gaming years before the rest of you suckers.
The whole 3d idea sounds pretty stupid, but it hasnt really been used in awhile it'll be nice to see how it turns out, although it probably wont be very good. Won't matter though, sounds like its only a small part of the game anyway, its not too intrusive, and its just a stupid pair of glasses that'll obviously come free with the game, i really doubt it'll make or break Sly 3 in any way whatsoever.