In reality, there's just one set of rules, but the way they are applied changes with the season. This is not a recent development; it's a point that has been made repeatedly over the years.
The Bruins were called for 9(!) penalties against the Senators tonight to only 4 called on the Senators. They were able to overcome the unbalanced officiating for the win in overtime, but this is starting to become too much of a habit, that at some point will cost the bruins an important game.
Tonight, they were lucky to be playing Ottawa, but if this happens against teams like the Lightning or Panthers it could seriously do some damage to the Bruins. Bruins fans want an explanation for the biased against the Bruins when it comes to these calls!