I think that would be hilarious but I'm a big fan of creepy crawlies and a chance encounter with a ticked off rattlesnake would not deter me too much. I'd keep my distance, realize it wasn't alive, then think "Hmm, fake snake very close to cache coordinates? Maybe I'll take a look!"
It's the caches with things inside that move or jump out at you that get me. I almost ruined my pants at a rattlesnake themed cache where a springy, noise making snake jumped out of the pill bottle!