Best thing to do would be for Linode to generously reimburse these people, but they have no obligation to do so.
As a policy, it would neither be good business nor appropriate for Linode to assume all of the risk in a situation like this.
Also, if Linode did put a policy in place to assume some of the risk (some sort of insurance policy) they open themselves up to scams (just get your friend to rob your bitcoins and cash in on Linode's good will insurance policy).
The scam you mention would be difficult to pull off as there would have to be evidence that the account was compromised on Linode's end for the customer to make a claim.
As a policy, it would neither be good business nor appropriate for Linode to assume all of the risk in a situation like this.
Also, if Linode did put a policy in place to assume some of the risk (some sort of insurance policy) they open themselves up to scams (just get your friend to rob your bitcoins and cash in on Linode's good will insurance policy).