Sometimes ignoring them may be the most practical solution, although there are situations in which it is acceptable to ban these users, and thus prevent them from continuing to grind (at least with the same username).

Yeah, that's exactly the fine line I was referring to in the beginning.
I'm a generally kind person, so I also don't want them to convert me into a flagging madwoman :-D That would be completely against my above mentioned values. It's hard to find the right path.

I guess I will be thinking about that a couple of days more...

Thanks for your valuable thoughts!
Have a great weekend :-)