I believe the OP is asking about the construction of the female QD receptacle itself. Some choose to have a liner, usually a metal ring (stainless?) whereas others do not. The few failures that I've seen reported have been in the cheap replacement set (foot/plate) and all have involved liners. It doesn't indict the concept of a liner per se, however it suggests avoiding the cheap brands. Over time, wear could certainly become an issue, and failure is certainly a possibility. I frequently inspect the holes for any deformation or visible wear and have found none so far with my Hejnar feet/plates. One could always email Chris and see if he has load tested his plates? As an aside, none of my firearms have liners (I suspect that the sockets are made of steel versus the aluminum alloys typical of most feet/plates) and I always use tethers on my camera equipment.