Kwik Fit Guy Refused To Change My Tyre

Having recently found a giant screw embedded in my front driver side tyre I decided to get both changed, as the threads where pretty low on each.

I set up an appointment with kwik fit, which was today, but after taking the old tyre off my passenger side the Kwik-fit guy told me there were 2 buckles on the inside of the alloy. I could see them myself so he wasn't making it up, but he refused to fit the new tyres since he said it would be his job if something went wrong. I spoke to his manager, who agreed to fit the new tyres for me himself, but told me to keep an eye on the passenger side tyre.

I'm wondering, doesn't ford check for this sort of thing at a service? My last service was 6 months ago and i haven't hit a pothole or curb since then, I'm positive, and it was in 2 separate places. I have the 17" alloys by the way, and until today thought i was one of the lucky ones not to have suffered from the extremely common buckled wheel problem. Maybe ford has decided not to mention it to customers if they think it's not too serious a problem, to try and cut down on the amount of complaints about the quality of their alloys.

Either way as i explained to the Kwik Fit guy I've been driving around on them for a long time with no problem and no leakage, and after spending a lot on the new tyres i really couldn't afford to get a new rim, especially one that i don't actually trust to last now anyway.