I used to give feedback as soon as I shipped the item. Then buyers started playing games - mainly using feedback extortion schemes - and I stopped giving feedback until the buyer was happy. I refused to be held hostage by some schmuck who wanted to get something for free ("I'll win the auction, but then used feedback blackmail to get a reduced price so I get over on everyone!") or to use my machine as a "parts source" for their broken item, then claiming that mine doesn't work as advertised.
That is what happened here, too!

In cases where that was a possibility I'd put one of those mylar tamper evident stickers over one of the screws on the back or bottom so I'd know if someone took it apart. Initial it with a sharpie and nobody can open it w/o you knowing. I'll have to ask dad to snag me some more of those before he retires at the end of the week...

-Jay