Fair enough, i stand corrected on the point. though all those requirements could be vitiated with a hard fork. Which you and dan probably have enough votes to get if you want to. And you can and did (IIUC) shut down those accounts' WD and transfer abilities while you were figuring out the hard fork to allow for account recovery.
The point being, its fairly clear that if the powers that be decided they didnt want someone to have their steem for some reason, they could stop it from happening. I powered up 4000 yesterday, which speaks to my belief that it isnt going to happen, but yeah it absolutely could. The system is definitely not trustless like BTC, it depends on the integrity of the central elements...