2x the collateral price worth of Hive is moved from useraccount to the hbdcollateral account and HBD is created and deposited to the user account.

This seems over-complicated in my opinion, more so if you account for the fact that when the operation is finalized the median price is used to make the conversion.

The comment about doing it in that way because it's good PR doesn't convince me that much. As long as the code accounts for not exceeding the 10% debt ratio it should be good enough.