I think the all-time exhibit A for playoff clutch has to be Claude Lemieux:
379 goals in 1215 regular season games
80 goals in 234 playoff games
Scored approximately 31% of his career goals in the playoffs, while only 16% of his total games were playoff games. That's a hell of a difference. If I had to make an argument for 'clutch', it'd be Claude. As in Bennett's case, the ability to get away with more rule infractions around the prime scoring area in front of the net is surely a part of the equation here. I'd like to think that with the opposing defenders also able to get away with more in the playoffs, there is a balancing out that doesn't make this as big a factor as some might believe.