The problem isn't (just) that this might hurt would-be theives. It's that it harms indiscriminately for anyone that tries to lift the item. There are any number of reasons that someone may legally and in good faith try to lift your cooler. Including but not limited to:
-Your cooler fell off your boat, and someone was retrieving it for you.
-Someone thought you stole their cooler and they were lifting it up to look for identifying marks or a name/label/sticker to verify.
-They were a guest that you forgot to warn or who forgot the warning.
-They're a law enforcement officer preforming a warranted search of your boat.
-They're a first responder trying to move the cooler to make space to resuscitate someone.
And even if none of that were the case, defense of property must be reasonable and proportional, and never outways human life. Injuries like this can leave someone with permanent impairment to the use of and feeling in their hands. It can also be a serious risk of infection that can kill someone. None of that is acceptable just to protect your Yeti cooler, my dudes, particularly when less injurious means of protecting your property, like storing it, tethering it, or using technology like a trip switch, alarm, motion sensing lights or a camera are options as well. Is it OK to steal? No. It's it okay to maim indiscriminately to prevent theft? Also no.
It's nice to see Lemmy will be continuing Reddit's tradition of believing booby traps are ok because anyone trying to touching your precious things deserves the be physically hurt, regardless of the countless ways it can hurt other people who were doing nothing wrong.
This example isn't even defendable from a home defense angle because you left the thing out on the damn boat, not locked away. At that point it's not just a booby trap, it's a baited trap.
And for fucks sake it's a damn cooler, who cares this much about it but leave it where anyone can get it?
And if someone picks it up in good faith? Trapping something that is locked away and could only be a theft attempt is one thing, but this is a cooler sitting out in the open. There are plenty of reasons a well-meaning person might pick it up.
This isn't reasonable theft detterent, this is sadism.
Ah yes, legal eagle has a good video about the righteous chaotic good farmer protecting his abandoning abandoned farm house from some kids by setting up a shotgun trap.