I don't know what's got into the cat population of South Cambs. Over the past seven days we seem to have had nothing but calls about sick or injured strays, mostly turning out to be very old cats with "senior citizen" problems rather than traffic injuries or infections.
I can only think that some of them are ones who don't go out unless the weather is really nice so that the neighbours don't normally see them. Many old cats do look thin, so from the neighbours' perspective it's not unreasonable to assume that the unknown cat suddenly appearing in their garden is lost and thin through lack of food. At least two of the current crop turned out to have owners who were very distressed that their pets had apparently been "kidnapped", and of course it's potentially quite dangerous if cats who are on medication are removed and don't get their pills at the correct time. There's also the worry that some owners may not know how to search for missing cats—unless they phone round vets and animal homes rather than relying on putting up posters they may never trace a cat who's been picked up as a stray.
I can't stress enough how important it is to ask around and put up notices before insisting that animal welfare charities should take away an apparently stray cat who is simply thin and somewhat unkempt-looking, rather than having any obvious injuries or infections. Removing an owned elderly animal is stressful and potentially dangerous to the cat and can cost the charity hundreds of pounds repeating veterinary tests which the real owner may already have had done.