I don't even understand what the problem is with requiring playoff rosters to be cap compliant. I remember the explanation being that it had something to do with players not getting paid a salary while in the playoffs. Surely they'd be able to make what should be a relatively minor change to the CBA to say that the cap is still in place despite salary only being paid in the regular season.
My understanding...The CAP is specifically set based on HRR, and HRR can only be "predicted" based on the regular season because you know how many games will be played and how much revenue will be generated. With the playoffs you don't know how many games will be played and how much HRR will be generated, so it messes up the formula...plus the owners want all the playoff money in their pockets... And I'm sure it's way more complicated than that, but regardless, if the NHL wanted to stop teams from doing this they can figure ways to do so.
- make it so every player that plays in the playoffs had to have played at least 1 regular season game
- apply whatever amount you go over the cap ceiling in the playoffs as a cap penalty for the next season
- Use the cap ceiling , each playoff game has to have the filled out lineup card be less value than that amount based on what the players made during the season.
These are just examples. Like I said, if they want to stop it they can.