I never did buy them. I was looking for small quantities... I only needed two screws and I just couldn't talk myself into spending $50 for a box of a hundred.

In the end I just drilled holes into the bottom of the hex socket of a couple of ordinary stainless screws and inserted a bit of heavy gauge stainless wire into the hole. The net result is pretty much the same as the tamper-proof hex screws referenced elsewhere in this thread and works fine with the Bondhus wrenches.