I think the threshold would be, did Linode take "reasonable" precautions in protecting the servers in question. Just like the landlord or bank. So long as they take reasonable precautions, they can't be held liable.

You can expect for your landlord to keep their copy of the key in some sort of lockbox, but you aren't going to expect them to keep it in a pressure-sensitive safe, guarded by movie-style lasers and a German Shepard.

You expect a little more security out of your bank.

The real question is: why were services that act like bitcoin banks storing their coins on Linode in the first place.

It all comes down to insurance. No one generally pays out of their pocket, they pay with insurance money. The reason you pay so much at a bank for a tiny box, where as, space wise, you pay a fraction for your appartment, or essentially change for a storage locker, is that the bank expects you to put valualbles in that space and so pays lots of that money to inssurance so if they do get robbed, they are covered and can pay you. The other places... dont. And usually have clauses in their contract saying as much: "We aren't insured for valueables, so don't store them here, it may not be safe and we won't (and can't) pay you back if they get stolen.

Linode falls into the second category, cheap, uninsurred storage space. You want storage space insurred against digital robbery, a) good luck b) expect to pay a lot more than $20 or $30 a month