The act of stealing one's guitar picks. Term can be used in general stealing, or more specifically-stealing from another one's pocket.
There are usually a vast amount of pickpocketers (those who 'pickpocket') at your local Long and McQuade Music Store.
My stupid friend pickpocketed (past tense of 'pickpocket') me the other day...now I have to finger pick. DAMMIT!
Next time I marmalade (See "Marmalade"), I hope nobody pickpockets me!