[exclusiv]

Valid question but the reason is the mechanics in the back are usually a salty kind (and some drink a LOT in the back) and they'll get a call to fix a lodged pin or something and decide to not turn the power off and bad things sometimes happen. I knew one back in the day that ripped up his arm really bad and had to take a lot of time off.

[JohnFen]

In those cases, the fault isn't the machines, it's the negligence of the mechanics.

Where I work, we produce industrial machines that could rip you in half without a hiccup. As a result we (like all industries that use hazardous equipment) have a very strong lock out/tag out policy.

I remember in training they warned us that at customer sites, it's common for the customer's employees to be averse to LOTO because of the time and hassle involved, and they may try to pressure us to skip LOTO procedures. We are expressly prohibited from doing so, but the negligence is real.

[exclusiv]

100%. My father in law has spent a lot of time in industrial space and he told me they setup dual buttons for some machines so you are required to press them both with both hands. This prevents them from having a free arm at risk.

You have to prevent people from going rogue, otherwise they will.