Haven't come across a chain my battery angle grinder can't remove within minute. The chain gives a phycological barrier but not much more.
It is a poor show when you feel you can't just say no and that be the end of it. I get the impression the man is a bit of a bully and I don't like that kind of behaviour.
I totally agree, but that then is criminal damage to gain access. A whole new bag of worms...