Pffft.
A list of "members" would mean that vampires and hunters would have access to this list. But given that you've only mentioned showing this list to Defense Force members most of whom wouldn't be on the list and those that do are more likely hunters than vampires...that doesn't answer my question of how it is better for vampires to be on this list. If it's not something that is beneficial for everyone involved, it's not much of a solution.
If a vampire causes a problem, you'll go to a hunter on that list for help, but if a hunter does something will you think to call a vampire first? Probably not. [And Rayflo was more referring to people like a certain black-haired demon king who don't know how to keep their mouths shut longer than it takes to finish a vowel. Malicious, no. Stupidity, yes.]
Would the list be voluntary or mandated? What would you do to a vampire who didn't want to register? All a hunter has to do is deny being a hunter. Vampires don't have that benefit. [And Suzaku knows that.]