My friend has done it a few times with like a half oz or an ounce at the most. We've never really talked about it, but I actually did smell his guitar with his pot in there, and it only smelled a little bit like pot. I mean, the baggie was completely rolled up and locked tight and all that but you could still smell that shit if it was out in the open 5 feet from ya.

To answer your question, I'd say no. After we took it out, it just smelled like guitar wood (it was an accoustic one, i think?) I've also used my PS2 to stash shit alllllll the time, and it STILL don't smell like pot.

But, with anything, if you constantly expose something to the smell of something else, its gonna smell like that thing. Case in point, everytime you get weed, hide it in your guitar cavity. Don't smell the guitar cavity for a year. Now, in a year smell it, and come back and tell me if it smells! It will!

but.......thats a year from now! So, I'd say screw it and go ahead and stash it in the gi-tare!