Then you need an expert on the equipment. If the person who tagged it out didn’t document why, and isn’t available to answer questions, then someone needs to do a full diagnostic and maintenance on whatever it is. Really, asking the person who failed to document the reason shouldn’t even be considered an option. Memories are unreliable. Anyone with the authority to lock out equipment should be trained on the procedure.

The original person who locked the switch fucked up, but that sort of fuckup is precisely why LOTO procedures exist. Safety regs are written in blood. 500 years ago, some well-meaning technician found some equipment that was broken and put it aside to fix later. One of their colleagues found the equipment, not realizing it was broken, tried to use it and immediately died a gruesome death.

Safety is diametric to convenience. Somebody cuts a corner somewhere, and the safest thing to do is overreact.