They are assuming all other principles are satisfied.I don’t believe a 7 seed is sent to a site based on proximity. It’s only for the top 4 seeds of each bracket (top 16 overall)
“National Seeds
Before any games get underway, it first begins with the seeding. The top 16 teams of the tournament are assigned what is called a “national seed”. This helps shape the tournament and designate who is playing who, and where they are playing upon advancing to the next round. Each team that is assigned a national seed is granted hosting rights for the regionals round.”
Source
That's how Auburn got Birmingham. Saves money on travel for the NCAA and keeps teams from losing time traveling if possible.