One side of the bar with the studs fell through on mine and somehow got swung around inside. It would not swing back so I could put my finger in the hole on the one side and push it back through. Took it to a dealer on a Saturday and the first thing the Service Manager says is, "Looks like we're gonna have to take off the back tire!". I told him, no, I'm sure one of the mechanics can figure it out. They put a scope inside the hole and the other stud that was stuck inside was caught on some wires. Pushed the stud that was remaining above the fender down a bit and the stud inside freed up and swung back around so it could come up back through the hole. Since this was the second time it had fallen through I bought 2 new nylon washers and they hold much tighter. Not a great design. I think tacking it to the fender might be a good idea to keep from having to deal with this again!
They didn't charge me for it, just a hassle. Your GF must have some tiny hands and arms to get underneath the fender to do that!