[TXnMA]

"sabotage?"

Not necessary. Happens all the time to infrequent boaters without a pre-launch checklist routine. See my http://www.freerepublic.com/focus/chat/3881322/posts?page=22#22

Besides -- many recreational boaters actually don't know how to use these:

They are adjustable: the diameter can be expanded or reduced by turning the handle and/or the nut on the other end -- to produce a snug fit and seal when the handle is snapped over 90 degrees as shown.

Water pressure can push a too-loose plug out of place and into the boat. You'll never know there's a problem -- until you slow down -- and suddenly find yourself ankle-deep in water -- and the plug missing in action...

I'd list ignorance, forgetfulness, carelessness, "rush-to-launch" and "impairment" as probable causes -- long before I'd suspect "sabotage".

~~~~~~~~~~~~~~

"Never attribute to evil that which can readily be explained by stupidity and forces of nature..."

TXnMA    
  

"Hop in and hold muh beer -- while I back 'er in..."

[RitaOK]

LOL! Case solved. Book closed. :D

[Pajamajan]

"Hop in and hold muh beer -- while I back 'er in..."

🍺- definitely the leading cause of many problems.🙃

[SheepWhisperer]

Every drain plug hole I’ve ever seen is threaded to accept a brass plug. It can be tightened down to where nobody would have enough leverage under water to unscrew it with Wrench.

Why on earth would anyone use that wine stopper contraption? I carry an extra plug and even it too is brass, tied to a float as an emergency spare. I’d never consider a wine stopper.