My reputation is normal, so I still don't understand why this is happening.

I think you're wrong because i never had that prank happen to me when i was playing? did you know you get diff pranks if you have bad, normal, good or loyal reputation? you can check them in the wiki

I was thinking about nails... But looking at the number of objects in my base, I realize I won't have time to nail down absolutely everything, and besides, it's unclear where I'm going to get that much metal scrap in about two hours of play (I had a save that happened).

Even taking all of the above into account, what's the point of a setting like physics events? Even with it disabled, physics events still happen and all your items fly off in different directions, so I'm guessing it might just be a bug, since I highly doubt this setting was added for no reason.