Interesting take. I hadn't seen that argument made as much as calling her things like slut, whore, pimp/madam--all of which imply moral preening moreso than care for her life span.
I'd argue her drug use is a lot less well-known than the underage drinking and such going on at the frat parties... If the police aren't raiding the DIK house every evening, I'd say Quinn's pretty well shielded (for now). Especially considering she's apparently not the ringleader of the drug distribution ring. Possibly could be the start of a whole whodunit plot line if Quinn somehow gets outed/arrested and snitches on the supplier, but I don't see her personality so far leading any credence toward her being a snitch when under pressure.