Pretty much all Leatherman pliers rely on the "lip" as you call it Paperclip. As do the Victorinox tools, Bear tools, Gerber butterfly-opening tools, etc. It is a pretty stout and well proven system.
The sheet metal stop on the Multitasker is about 1mm thick also.
It must be a proven design then
Thanks for informing me, J-sews.
Do you follow what I'm saying?
I think I understand the gist of what you're saying, and the rivet is of greater concern when you're turning a nut/bolt especially with the MT perpendicular to it, but actually I was thinking about cutting wire. After hearing your story and people breaking pliers heads however, perhaps the lips are pretty stout afterall