The situation you describe could become more common in the future as a result of the Jordan situation. If a team is looking for a star at a certain position - say a center in this case, they may make offers to multiple players to hedge their bets in case one of the players decides to withdraw. Once the moratorium is lifted, the team will try and sign their contract with their #1 choice, then tell the other(s) there is no longer a spot for them.
Honestly, this situation is much better for the player than the team, so not sure the league or players association would try and stop it. If you are Dallas this year, you get screwed. All the stars at center have already signed elsewhere by the time you find out Jordan pulled out, and you get nothing. If you are the #2 option for them at center, and they say thanks but no thanks, you can then move on to other teams. And by receiving offers from multiple teams, the player may end up with a better contract in the end, then if other teams are scared off by the leaked 'verbal commitment' noise during the moratorium period.