OK, one last time:how do you seriously "accidentally" pack away a sink plug?
REMOVALISTS REMOVALISTS REMOVALISTS REMOVALISTS!!!!!
They are good at lifting heavy things, often not so good at distinguishing between the occupant's contents, and fixtures/accessories.
As well as plugs, a doorbell, doormats, and other items, I just remembered that I've also had a removalist pack the remote control unit for a fixed air conditioner.
Trust me - it happens - and not infrequently!
But I am now also at the point of rolling with laughter at how ridiculous this discussion has become.
And chris01, that kind of plug is called a "basket waste" and it's hardly exotic; they're standard on new sinks. But $20 wasn't a bad guess.