Edit: To be clear, I'm not defending that practice, I'm simply pointing out that it doesn't seem to be uncommon and it's apparently enforceable.
diagnosis: nonsense
treatment: contract law 101
Then I'm at a loss for why bitcoinica didn't go after Linode? I'm sincerely asking here, I don't know much about contract law. Was it perhaps because the entirety of that theft was in bitcoins and bitcoins aren't recognized as having any value (I don't know how that would be the case)?
Bitcoinica got $350k stolen from them in 2 different hacks and they didn't report it to the police. What are you expecting? Miracles?
Add to it that those thefts, even without the theft of the bitcoins, would be a crime of computer intrusion and it's even more surprising that none of them were reported to any authority.