It would be difficult to maintain the same financial barrier to setting up a rogue node without integrating the exchange into the core daemon, which I don't think is a good idea, for financial/legal liability as well as security reasons. But you could in theory implement a similar but separate requirement for exchange nodes.
Are Masternodes themselves ever charged collateral fees? I don't see how they can be, the MN balance remains locked up.
I think a far simpler approach to a decentralised exchange would be to just keep trades between individual buyers and sellers. Any 'depositing' anywhere and you're back to Bot Town.
I agree
Buy to seller .... seller to buyer .... keeping it simple but save !!!
(DRK - BTC ... BTC to DRK ONLY)
So what about Smart Contracts ?!
I sell 10 DRK for BTC (smart contract) with Escrow !
You buy 10 DRK for BTC, smart contract sais YES (as payment is correct) does his signature, I do mine .... 2 out of 3 (Multi Sig)
Escrow release and done !
Everybody Happy ?!