We could use a Preferred/Blocked player list for DF.

[MoraClaret]

The problem is that there are a lot of people with the same names as each other, so unless it has the extra function of checking players across all the servers, you'd be potentially blocking a lot of people who don't actually deserve it.

This system would have to include World of origin.

Like you could have Bob McGee [Behemoth] on your Preferred list but Bob McGee [Cactuar] on your Block list.

It is very likely that the player's world of origin is already included in the logic for matching to begin with.