I've looked after grandchildren for their working parents for 15 years. Very few things have ever been broken and I'd never tell off a child for an accidental smash but I think the parents should offer to pay.
When little grandchild picked half the keys off my laptop my daughter said, "Well we can't afford to have it repaired". Neither could I.
What have others done when grandchildren break something expensive?
The Lockdown GangSTARS still going
Feeling horrible after a 'near miss'
Loving the common thread so much thought we should go “POSH”