Agreed. I would hope that our GM does the same thing if the opportunity ever presented itself, but I do hope they change some rules.
I have a couple of thoughts on ways to address it:
1. Your dressed roster for a playoff game must be cap compliant. During the regular season, your scratched players count against the cap, so this would be a bit more lenient, but at least in theory, the players that are playing in the game fit under the cap.
2. If a player is on LTIR for the entire period from the trade deadline to the end of the regular season, then they have to miss some playoff games. The most lenient option would be a single game, the harshest option would be the entire 1st round. Maybe 4 games?