Well, next time I will ask the charter company: "If the boat suffers such damages, who will pay?" That's not a guarantee, but at least I could undertand their policies.
I've had some damages on my previous charters (I took the boat from an Austrian company in Turkey). Once the fender
was squashed (other boat moored very close) - charter company manager have seen it but didn't even mention, the other time inflatable
lifejacket was accidentaly inflated - they charged 50eur for that.
And of course you have to check what you can but you can't check everything. For example we had a problem with motor battery overheating
when dynamo failed. The battery
was very hot and very strong smell of evaporating acid filled the cabins. After such a destructive procedure you should change the battery and I said that to charter company manager but his answer was, like: "Oh, it's fine, it will work". Well, it will work for a while, It will show ok voltage on the voltmeter, but can fail, it will not hold charge if half the acid evaporated. But that will be the problem of the nex charterers, I think. I feel sorry for them but I did what I could - reported to the coast guard.
And yes, probably the bank could help if you use the credit card. But no guarantee - vlathom
mentioned here that he wasn't able to recover the lost sum.