Unless we're lumping everything together (some of these certainly go with drinking), I think it's lots more than "just" an alcohol problem, slash--although I agree that every player should at least be given consideration. Here are some of Smith's non-drinking issues:
1) Suffered stab wounds at a residence where two people were shot. Charged with illegal possession of an assault weapon
2) Hit and run + leaving the scene of an accident
3) Claimed to have a bomb during an altercation with TSA workers at LAX airport. Obviously uncooperative with police and airport security
4) Possession of marijuana
5) Vandalism
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And then, as you mention: THREE DUI's, at least one known rehab stay, and a suspension which lasted for the majority of the season.
The third DUI alone calls for jail time, as it should. Smith will almost certainly be out of football until 2016 at the earliest, but I'd have them look into giving him another chance once he's out of this mess.