Unless it's something dropped by an ally or as part of a mission anything you pick up will be marked as stolen (and therefore can only be sold on the black market) and if any law enforcement scans you with it (a very good chance since the new beta) in your hold you'll get a bounty in that jurisdiction, so now point having red or green cargo scoop scanners coz they'll pretty much all be red. As for griefers dropping cargo for noobz to pick up, dropping cargo within the no fire zone is now a crime too, so the griefers would quickly be running from the law too (and dropping it outside the NFZ won't have much effect).
Basically, if you pick up stray cargo you better be ready to run for a station with a black market and no vipers.