Back in my TV Engineer days working at a local ABC affiliate, we had this giant degausser that we used to bulk erase videotape cassettes for reuse.
Whenever I heard someone else say something stupid, I would jokingly turn it on and place my head on it, then give a sigh of relief with my newly erased brain.
Who knew that I was really onto something.
In my younger days I had many roles on the fire department that I worked for. When staff was short I would be sent to the 911 dispatch center. WE had a limited number of tapes that were used to record 911 calls. After a few months we had to erase them, so this was a daily duty using a degausser probably similar to the one you described. Ours had some type of warning label. I have no idea what it actually said. But it is funny that some people who wear magnets around for some type of perceived health benefit are afraid of other forms of magnetic fields. We had a few people who refused to go near it even when it was off.
Bet it wasn’t as big as the Navy’s degausser...big enough for 600 foot vessels...don’t think there was ever an issue with the crew’s minds being wiped. At least I don’t recall....