Given the age of that particular crampon, I'm guessing the owner is doddering, senile, and doesn't know he's missing it.
Probably walking around the old folks' home with the other one still on, and threatening the nursing staff with a Forrest ice tool as they try to get him to hold still for his enema.
(I jest, I jest. You old guys/gals getting it done with that gear have my sincere respect. I can barely climb out of bed with monopoints and Nomics.)