Hello
My cat just last week came in with no collar, she has lost 4 in a year. They collars are not cheap, she also has an engraved name tag. I also have looked for the collars, but never found one. I always think they have done there job by releasing in times of need.
However To loose 5 in a short space of time is a bit much. I would be looking around the neighbourhood cats for the collars, could the owners get so near to remove them though?