Hit to the head.
In the BCHL you’re out of the game, pretty much even if it’s an accidental thing or not. Why should the NHL’s standards be any different? Isn’t the NHL ‘smart hockey’, too? Don’t these players care when they sign papers promising to abide by the NHL’s rules governing this game on & off the ice…and emphatically agree NOT to deliberately harm or injure one another, when they sign their contracts as union bros?
If accidental…& you forcefully hit someone in the head - you’re probably still being reckless.