Currently, if a Player Tag has been selected by a port and that port has been turned off, the Player Tag does not become selectable.
One has to set said port to a CPU to make the Player Tag selectable.
The short of it is: Make Player Tags selectable when no port is active with that tag selected. It would make the LAN experience at local events much better. A huge QoL change, IMO. Especially when playing in rotations where people are unplugging and replugging and Player Ports are changing - which causes Tags to get mixed up, by the way.