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Why are you comparing DRK to POS, the collateral for masternodes simply serves as a means of proof of service... there is no staking involved. DRK is and always will be, a POW coin.
I am comparing DRK to POS because the economic incentives of running a DRK masternode are essentially the same as staking a POS coin. This means both the security "cost of buying up enough DRK" to attack the privacy of the coin by controlling a large number percentage of the masternodes and the possible attack by "borrowing the DRK to set up malicious masternodes" are essentially identical to the economic incentives in a POS coin. The compensation is also the same since a portion of the mining rewards are diverted to the masternodes. This in effect makes DRK a hybrid POW/POS coin with transactions secured by POW and privacy by POS.
...again, good luck buying or borrowing enough DRK to even pull off this terribly unrealistic attack vector on privacy. Even if you owned HALF the masternode network, you still have probabilities far too low for any substantial analysis to be quantified. You would be far better off trying to rent hash to perform a 51% attack then you would trying to buy/borrow coins to deanonymize DS txes. It's a waste of resources. Now you're just getting silly.
As for your regulatory attack you keep adamantly bringing up... try to realize there are other countries outside the United States. While the US is a juggernaut, it wouldn't be a death blow if nodes were hosted elsewhere. Having said that, again, guidance as per FinCen, masternodes are not MSBs. There are far larger ramifications if they were, including Bitnodes and Monero's full nodes as well.
Side note, I do love the name and agree it is one of the strongest names beyond Bitcoin.