Encouraged by MLB? One could take that approac as they were not in the collective bargaining agreement, but it's clearer now that is a Union issue more than a MLB issue. Regardless, beating a player with a bat during BP so he can't play against you that night is not in the Collective Bargaining Agreement, but the laws of the country surround assault and battery would supercede that of the CBA. Illegal steroids in the USA suddenly did not become "ok" because it was not part of a CBA... and Fay Vincent outlawed them anyway. I beleive Kuhn has some language about them as well.
With no testing allowed by the CBA due the union, it was up to the players to follow the rules and laws. If they didn't then that is on them.