In my opinion, pins are something to be avoided at all costs. I'm with eHalcyon there.
Although honestly, the only pin i really know of would be the Masquerade one, and that pin only exists if several cards appear and the game is a 2 player one. It looks more like a (far from trivial to catch) oversight. Torturer is not a "pin". You can just gain Curses, which is a good idea more often than people think. Saboteur is not a pin, though it's clearly very close. Usually, Saboteur's just too bad to make this work. In either case, you could just buy Coppers, Duchies on $5 hands and gain Estates when your Duchies get trashed. And, well, hope to have your one Silver in hand when Saboteur is played. Knights are probably the worst, as Sir Michael is also a discard attack and could technically limit you to 3 cards a hand, but even then the "hope to draw my only Silver to buy a Knight/Duchy" thing would apply.
A debt attack that gives debt on buying cards is not a pin. You only get debt when you buy something, which is not only something you decide on your own, but also what debt keeps you from doing in the first place. Debt would actively keep you from getting debt.