"Pinch blade connection" is common today, in every type of electrical connection. I believe that type is the source of many house fires for the reason you ascribe. Look at the cheap sqeeze together 12V wire taps used by most, to add a RV Bargman plug to a tow vehicle, RV manufacturers to install electric brake wiring, etc., and how many electrical failures that are experienced from their use.
Cheap is cheap, we really do get what we pay for!
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"