I've come across this too, idiots who buy old knackered waterside houses next to the canal and moan.
I will be honest, people like this don't realise we have the same rights in law and threats is bloody hard to deal with.
Some people think we don't have the same rights and just see boaters as travellers who I respect in every way.
Living on the canal you have to be multiflexible in mind, theirs a lot of characters out their. (Think Live Aboards know this one) lol for sure....
Threats just not on.
Better to report than doing other !