We renovated a house last winter and it had old UPVC windows with locks on, that were being replaced. There was one key for all the windows, which were all locked. The old key was bent and eventually snapped off in one of the locks. The customer was giving me a dressing down moaning she could not open any of the windows, as I was pleading that they are being replaced anyway. So I stepped over to the top opener and snatched the handle up and opened the window for her and walked off and said "is there any more you'd like opening..."