Last week my copier refused to work properly, so I called the manufacturer. Thankfully, the thing is still under warranty, and today they sent out a woman to fix it.
She explained the nature of the problem (seems to be the design of the machine), which, most importantly, wasn't my fault.
I may or may not have used unauthorized toner in the machine. I'm not admitting anything, and she didn't ask. She simply informed me that if I DID use unauthorized toner, it would void my warranty, and any repairs would be charged at full price.
I would be shocked, SHOCKED, to find anything unauthorized in my copier! ;-)