I had some cheap microswitches, and one had failed, but we figured that it was just one in the bunch, and put it into the interlocks of a laser cutter, to replace a switch that had started to fail. Then a second one from the batch committed suicide in my hands. This may have had something to do with the fact I was taking wires off and the plastic casing melted a bit, but it was Not Good. And indeed, Demonstrably Not Safe.
So, that’s been swapped out. And I’m off to eBay to find some that look like they were made by the /second/ lowest bidder. Cheap is good! Except in cut-out switches.