No, wouldn't that be a good thing. Better than finding it in a casino. I'd be afraid to keep it seeing how the cameras are on you everywhere. I've heard that you have to turn it in if you found it in the casino b/c it's considered their money.
On my second trip to Vegas I did find $20 in the parking lot. I took my bags out of the trunk and when I looked down to pick them up there was a twenty on the floor nicely folded.
Walked right up to the first slot machine and played for about 2 hours.