I do plenty of work on the 79' Broncos I rebuild. To pay $90, for someone to install a $3,000 cover was more than worth it to me, but to each their own. They install these a lot, and they aren't as easy as one would think to install. If any warranty work was ever needed to be done, they would honor their work.
However the whole point of buying this cover, was that warranty work wouldn't be needed like it would be if you bought a Retrax. If you installed it correctly the first time, why would you need to find fixes? I think your point highlights why I brought it folks who install these daily. Plus if I scratched this nice cover I'm sure I'd be pretty bummed with myself. Cheers!