Tenants Live-in complaining of worker noise

[Michael Campione]

Anybody run into this?
We are having a badly needed roof replaced on one of our duplexes. We informed both tenants last week this would be happening this week. Today we get a phone call from the one tenant, that the other's girlfriend went out and told the workers they had to quit because they were making too much noise and to come back next week. (btw, she is not on the lease) I told the one that called to tell them to continue and I would be over.
The tenant on the lease is a good tenant. the girlfriend that stays over is the problem.
I am composing a letter that pretty much says the tenant will take full financial responsibility for any damage incurred over the weekend as a result of them stopping work.
Any comments?