That's not feasible as it would disallow the fluidity of line-shifts on the fly... which is a huge part of the game.
More feasible, but line-shifts occur with the kind of frequency that would make that more of a hassle than a safety precaution. Interestingly enough, I just read Pacioretty's comments about the hit, and he basically says the same thing as I did. He doesn't feel that Chara did it purposefully, but he also feels that if the NHL doesn't punish, then others around the league will feel like they can get away with stuff like that too.
The hit was legal but friggin dirty, if he did not get injured nobody would have had said anything. Players get knocked into the bench quite often. It's the leagues fault for having no rules or protection for players who end up in that situation.
