Pitlocks have a collar that surrounds the keyed part. That collar spins freely so you can't grab it with a pliers or vice grips. It *may* be vulnerable to the Gator Grips but I don't think so. If I recall, looking at my key, it doesn't have many areas on which the pins could grip but rather it's an irregular shape that has to fit into the key in entirety. I also don't know if the pin size on the Gator Grip would fit into keyway on the head anyhow.

Pinheads are really not much protection for the hassle they provide with their key to use. A vice grips is easy to conceal and cheap to procure. The speed by which they can defeat a pinhead is fast so there is good incentive with few obstacles for a thief to deal with them.

Pitlocks are more protection and a lock or locking them is even more protection beyond that. In a University setting, in which we use them, and in trying to get my kids to properly lock the bikes (a hopeless task) instead of the U lock just around a tube - the object is to become a much bigger hassle to steal and take apart for parts than the other bikes in the area. Pitlocks do that well when used with a substantial U lock. It just makes the bike a time sink for the thief by being too slow to turn into cash. Then, of course, the guidance it so park it next to the the most valuable or most poorly locked bike you can find. Contrast is always good.

J.