You can sort NHL statistics year by year at (e.g.) https://www.espn.com/nhl/stats/team/_/season/2026/seasontype/2/sort/penaltyMinutes ... and find documented proof that NHL referees are prejudiced against the Boston Bruins, who annually rank in the top 8 (at least) of most penalized teams. This can't be written off as team style because there have been very different coaching styles and player personnel over the time tracked by this site.
