they go into the discs on the back but not at the front, so fire on and you can change your front discs later at your leisure. If the body shop has a bench press they can do it easily, good chance they will, if not run with the hubs to another garage to get it done, two minutes. two things thought make sure they are put in the right way and that they seat flush with circlip, also slap on the supplied grease (with bearings). Also torque them right from the figure in hand book.
When bearings get really bad they break up, and this involved your hub coming off with wheel attached, so yeah could cause damage, but few people can put up with the noise, and get them fixed before, so this doesnt happen that often.