I spoke with the woman who was upset (and understandably so) about the cat defecating outside her home. It seems that she is very concerned as she is leaving the country for a few weeks and is worried that the problem may have gotten very bad by then. In fact, since she last contacted us in March, there hasn't been much of a problem.
At first she said she would ask the TC to round up the cats, but when I explained it wouldn't help, and I think coupled with the fact that she didn't want the cats killed, she emailed back to ask if we could look into other solutions, which was great news.
I told her about the Cat Stop and the Don't Cat at Daiso and she asked if she could buy the Cat Stop. I suggested she just rent it to begin with - in case it doesn't work for her, then she won't have wasted any money. I'm glad she's open to other solutions and is not just asking for the cats to be killed.