If I was Aquilini I would fight that in court. You can’t retroactively punish someone for something that was legal at the time. It’s like if alcohol became illegal then the cops go around fining everyone who ever had a drink. Absolute garbage.
It was very strange that all of these types of contracts the NHL didn't like and changed the rules for weren't "grandfathered in" to the CBA. I used to do a lot of labour negotiating as part of a union and most CBAs had some type of language like this.