It's on a case-by-case basis I'd say. Sometimes, it's worth just chillin' out and taking the PP, but if a guy seriously crossed the line (a la Matheson), I'd say it's worth negating a PP to send a message. In that particular case, with Stecher, it worked out perfectly, as the ref was gracious to us and simply added 2 mins to both Stecher and Erne's penalties, which meant we still came out on top, but that of course won't always happen and sometimes power plays can be negated. It's not a hard science IMO and should be evaluated by players based on the circumstances.