ERD50
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
I suppose I could, as it is definitely a case of encroachment and trespassing.
Although I'd prefer to have the neighbors remove it, as it is their fence.
omni
I'd try to approach them in a way where you are not the 'bad guy/gal'. Just say that you are thinking of selling, and you don't want this to become an issue that might affect the sale. You just want it taken care of to keep things 'clean' for any sale.
If you don't really care where the fence is, maybe offer to them that they could buy x% of your lot, and pay to get new surveys done and registered with the county, making the the fence on their property. Probably cheaper/easier for them to move their fence. But at least you offer an alternative. They might see moving the fence as the lesser evil.
If they don't act before winter, I'd start taking action. Send them a note from a lawyer, with a date at which you will have it removed and pursue them for the charges. See if a mechanic's lien can be placed on their property if they don't pay up.
-ERD50