The problem is not that the router is currently broadcasting a BSSID that exists elsewhere. The problem is that a geo-wifi database contains an association between their address and a BSSID.
They can change the router, and eventually the problem should sort itself out (if it is indeed their router and not a neighbor's that is the issue), but it's going to take until the old record ages out of the database for it to happen. And that could be months or years.
They can change the router, and eventually the problem should sort itself out (if it is indeed their router and not a neighbor's that is the issue), but it's going to take until the old record ages out of the database for it to happen. And that could be months or years.