Cheap extensions seem to be OK

My daughter went to a local salon and spent $75 having human hair extensions glued (bonded?) into her just past shoulder length, straight blonde hair so now her hair is waist length and much thicker. I was certain that her real hair would fall out, that the extensions would fall out or that she would have some other terrible problem. But she hasn't had any trouble so far and she has had them for over a week. The worst thing that has happened to her is that the hair ended up being sort of curly and since her hair is naturally straight and fine she didn't know how to deal with it after she washed it the first time. She has since figured it out and is doing real well. I guess I am wondering if this is normal or if we should expect something horrible later on. The stylist told her if she got tired of them to come back in and they would take them out.

Anyone have any opinions?