4G wireless/cellular to wired tethering (providing wired connectivity through a 4G device)

I'm asking for something simple, but not aware of a simple solution. I need to establish a wired Internet connection through a device that can support 4G operation.  Use case - at a hotel for a live networking demo, and the wired connection they provided in the conference room requires click-through acceptance through an AUP page (just like the guest wireless).

The problem is that we need a Cisco firewall (ASA) to establish a connection (wired) to VPN back to the home office for the demo to fly. The ASA obviously cannot accept the AUP policy, so we appear to be stuck.  (I believe the logging/Internet access is based on MAC address, so going through it with a workstation, and then quickly swapping the connection out w/ the ASA won't work. Correct me if there's an easy way around this.)

Any thoughts?  Is there a way to take a wireless device (like an iPad, whatever) that supports wireless, VPN it back to the office (thus bypassing the hotel wired connection altogether), and hook into its Ethernet port to support the ASA?

Thank you!