In reply to Andypeak:
I think "how not to highline" are just "HowNot2", now – and they're brilliant, and cover everything including caving, slacklining, climbing, sailing and paragliding. They test a bunch of stuff: go and watch them.
Their mission is to break gear-fear.
On topic: I rather like the Mammut 'NOT FOR CLIMBING' utility-'biners, myself, for purposes such as attaching the bag for my skins to a fixed point on my backpack so that it doesn't blow away while I'm ripping those and faffing about with their nets on an Alpine summit. (Thanks, Dynafit, for inventing the *white* skiing skin-bag, of all innovations …)
… but I particularly like them because, although the cardboard ticket suggested that they might hold 4 KN, the only printing on them is a big, bold font declaring 'NOT FOR CLIMBING'.