Imagine this... (Score 1)

I don't know what exactly your hotel guys said, but I expect once you're done with all the hassle, they will boldly advertise "Anyone visiting our hotel with a laptop will have instant Internet access". And then there come the problems. Imagine these cases:

• During their bold advertisemnt, hotel forgets to mention you need a laptop with a NIC for this. Believe me, many people - especially manager folks - don't know this :-)
  
• Laptop has NIC, but is usually used on an isolated network, i.e. has no default gateway, DNS-Server, whatever. The system wouldn't even try to resolve any names to ip addresses or ip addresses to mac addresses, it would just say "No"
  
• If used on an isolated network, laptop might not have TCP/IP installed. There's quite a few old Novell IPX and MS NetBEUI installations out there. Or it might have a modem, which is usually used for Internet access, and has TCP/IP only bound to the Dial-Up Adapter, while the NIC has only IPX and/or NetBEUI.
  
• Even if laptop has NIC and TCP/IP and a working browser etc., I myself have set up a number of networks where internet access is done via http-proxy. That means, the clients again don't have any default gateway or dns servers. The router/proxy/whatever you need to setup somehow needs to know that it has to play proxy server for these laptops. Others might be using a proxy accessible from the Internet as a gateway into their corporate network. How would you distinguish when to do transparent proxy and when not?
  

In short, I would try to explain that for reasons of security, simplicity and budget there is no reasonable solution at the moment. That's what I would do, at least ;-)