It doesn't cost extra to trap them
I just spoke with an office manager from a school. A volunteer happened to speak to a feeder in the area and it turned out the school was trapping cats. She requested I try and speak with them.
I spoke to the office manager whose first question was whether we were a non-government organisation and whether the service we provided was free. I asked if they were using pest control right now, and he said they were and I pointed out that hiring pest control costs money too. The man said that since the pest control was hired on a contract basis, that didn't cost money. I was trying to point out that it was factored in but it didn't seem to sink in.
He claimed that these were not community cats but 'pets' because a lot of people were feeding the cats outside the school grounds, but the cats ran in to sleep at night.
The office manager asked if we did not approve of the killing of the cats. I pointed out that it was ineffective as well as inhumane. He told me that I did not need to worry, the cats weren't killed - they were just thrown somewhere, far, far away, in his words.
I told him that this wasn't a solution. I said it was just transferring the problem to somewhere else. He told me he thinks the cats are thrown in reservoirs. I told him again this still wasn't solving the problem, so he's agreed to try the crushed mothballs to stop the defecation.
I also looked up the school on the map and realised that this is an area that seems to be having a lot of problems - a lot of people are feeding, but hardly anyone sterilises there. The office manager also mentioned a lot of people come to feed the cats early in the morning.