Hi Tempest, my mom is also a "bored never did anything in her adult life but service kind of person", but in her 80s. There is no logical reasoning with them, trust me I've tried on many levels.
The only thing that worked when I faced some issues with my mom was to say "I won't live like that or do that. If you want my help that can't happen." I'll spare everyone the details but it did work. She's asked about going in service in the neighborhood and I always say no, not safe and not a good idea. (It really isn't.)
My mom would go door to door in her old neighborhood and got sprayed with a hose once. I have no doubt that neighbor was just exasperated. She thought it was persecution, of course. But I have learned you just have to be blunt and consistent. Nothing else works.
I am a professional as well and shared your concerns about how this would be viewed by the neighbors.
I have noticed a lot of the older ones here have various forms of dementia, hard question to ask but could that be part of what is going on here? I do know the elders here would not approve of using a cart in that fashion.