I have had 2 of them for 15 or more years. I have seated primers upside down, sideways, 1 on top of another, and probably every wrong way possible. I use mostly CCI or Remington primers and have never popped one.

The only time I have ever popped a primer accidentally was depriming a LC 5.56 case that had supposedly been rendered inert by soaking in a mild acid solution. About every 3rd one was NOT inert. Just my $.02