I just noticed a user who is able to participate in chat despite not having any more than 1 reputation point on any site. Unless there's a hidden profile involved here, it looks like just joining 20 sites is enough to get chat privileges.
This specific user isn't causing any trouble, he/she is perfectly fine, I'm concerned that this rep totaling behavior can be used to get around the necessity of amassing some reputation before joining chat. Is this intended?
If rep summation should be usable to gain entry to chat but this strategy shouldn't, the algorithm could subtract one from every profile before considering it; that way, only earned points would count. There would probably have to be the extra complication of checking if any profile owned by the user has 20 points, otherwise one would need to get 21 points.