Not till they get hooked because someone else used them on them.
Using drugs on someone else is relatively rare - yes, drinks have been spiked with Rohypnol, but I know of no case ever of A having used (unspiked) marijuana on B.
I am not going to let you get away with confining this discussion to marijuana. Marijuana is just a stalking horse for full drug legalization, of which you have admitted to being an advocate.
Your stated beliefs are that all drug usage should be legal, including crack, heroin meth, etc.