The reason some Companies are probably charging an equipment Fee when hot swapping you from DirecTV's Service is because the DirecTV gateway (Router) is configured for DTV's network and has a proprietary setup on it which will not let it automatically interface with another network. As such they have to send you a new router..
There are a number of ISP's out there that are claiming to be able to Reconfigure direcTV's equipment but they still end up sending you equipment and charging you a fee. so don't get Suckered.
Also a couple facts about the DirecTV "Gateways"
They Are Routers -- They NAT, have Firewall's (Very limited) and do everything else that a router can do. They are not Bridges or glorified modems so don't be misled by what someone tells you.
DirecTV does not want their Gateways back, nor are they Charging the customer for not returning them. Again don't be suckered by another company claiming that. You can fill the things with concrete and use em as an anchor for all DTV cares.