There's been plenty of cases of goaltenders deliberately knocking the net off its pegs that the NHL needs to address.
During the Blackhawks recent game against the Arizona Coyotes at Mullet Arena, Blackhawks goaltender Alex Stalock gets his hand caught in the cookie Jar bumping the net off with his shoulder.
Not sure how the NHL can remedy this situation because they don't want make the nets almost unmovable for obvious reasons, but there's got to be something that has to be done to stop goalies from doing this.