Just thought I'd weigh in on this one as the resident paramedic from NYC. If for some odd reason a patient was hurt badly enough for this to be an issue, there would already be an engine on scene with extrication tools that are handy for this sort of thing. If, for instance, a jaws of life tool was not of any help, then the next call would be to ESU. ESU are pretty creative when it comes to these challenges. It does remind me though of the fact that titanium wedding bands are a generally a bad idea. The ring cutters we use can't cut through them. This has lead to amputations of fingers resulting from injuries as mild as sprains and fractures. But the waist mounted bike lock doesn't worry me too much, as the fit will still leave some room for the trunk of one's body to swell. Though ya might not want to wear such a lock while engaged in the Nathan's hotdog eating contest.