Nooo
Greenlighter
Like is it possible to be slipped LSD without knowing and have a good trip?
Mass spikings were big in the 60's and 70's at concerts. You could have a good trip as long as you figured out what was happening. If the CIA gave it to you, you probably wouldn't have a good one.
http://wzlx.cbslocal.com/2013/05/30/did-the-grateful-dead-serve-lsd-to-their-fans/
I don't see why it wouldn't be possible, but nobody really does this. As in being dosed unsuspecting of isn't really a thing, it doesn't happen.
OP if you are planning on spiking someone, don't. It's an exceptionally violent thing to do.