I can see it now - each lock would be connected to the hotel's wpa-wps network (shared with the guests of course) and use a dhcp server without static routes to assign IP addresses. Maybe if we're really lucky they'll be using some consumer-grade cisco switch with last year's firmware update.
Snark aside, they have to be _really_ careful not to fuck this up. There's so many potential attack vectors in this kind of system it's nuts.