This is exactly the sort of thing the new law in California is trying to prevent, absurd situations where people's lives could be ruined for no good reason:
Less Than 1 Ounce Of Marijuana Leads To Arrests Of More Than 60 Georgia Partygoers
After no one admitted to owning the stash, police hauled in dozens of people because the pot was “within everyone’s reach or control.”
http://www.huffingtonpost.com/entry/marijuana-ounce-arrests-georgia_us_5a4c5785e4b06d1621bb9898