[mrighele]

He would complain if he was forced to buy _only_ that brand's gasoline.

That's in fact the approach of many printer manufacturers regarding toner/ink cartridges, and usually users complain about that.

[sowbug]

I wrote "buyer," not "user" or "complainer." I have no problem with self-appointed Good Samaritans who leave anti-Lexmark Amazon reviews. But a buyer of a car requiring the manufacturer's gas would understand what he or she was getting into.