No professional sport gives a fuck if you smoke weed or take recreational drugs...what professional sports give a fuck about is if you are a stupid fuck.
Shit like drug tests are so calculated by professional sports and as an athlete, you are notified with a ton of time and/or only have to take tests during a specific time of the year, that if you fail a test...you are just showing the league you are a dumbass. Any fines or suspensions are less for doing the drug than being dumb enough to get caught.
For players like Mettenberger, the test means nothing.
However, I will say this...Seantrel's obsession with weed is well documented by not only UM (suspended numerous times for being a dumb fuck and getting caught) but scouts as well. Talked to one at UM's Pro Day and most teams supposedly think he's going to be one of the players from the class that smokes himself out of the league. Not a good look to get busted once again.