Ugh, that sounds like a serious q&a issue you'd suspect could only slip by Sigma, Tamron, Tokina or other cheap 3rd party manufacturers, but not a quality company like Canon. Probably for these rental companies, the had set up a special early delivery route that bypassed some q&a checks that apply to usual "off the shelf" customers?
Anyway, that should teach Canon to try to innovate with sensors, if they'd have stuck to the 18mp design this wouldn't have happened
It does not matter. There are plenty of people buying rebels. I seriously doubt that Canon is only shipping flawed sensors to camera rental businesses.