[Kitsa]

An update, of sorts:

I had to call the landlord because our dryer-vent was completely plugged with lint and our clothes weren't drying. When he came (removing both the log of lint and some ancient pre-us beercans and shuttlecocks from the gutters), I mentioned delicately that we were having a personal-space problem with the neighbors. I showed him some portable accordion-fencing from a catalog and asked if I could put up at least a couple, just as a territory-marker. He approved it.

It's a start. If they don't respect a fence, well, the situation is probably beyond hope.