Child Expense Coverage Etiquette...

You're at a friend's house and your kid breaks something that belongs to your hosts (here's the window pane on my back door that prompted this post).

The question is: what's the $ value threshold at which you:

1. offer reimbursement
2. insist on reimbursement
3. demand that reimbursement be accepted

Are there mitigating factors such as:

1. did your kid act alone?
2. the socio-economic status of your hosts? of you?

As the father of a son who, most likely, will put me in this position, I am looking to better understand social convention and expectation.