You can still bring the wifi antennas inside the venue and operate a wifi LAN.
The cage may block avenues for that LAN's access to the Internet, but in the worst case scenario, someone could operate a sneakernet bridge by shuttling large storage devices between the wifi LAN inside the doors and the WAN access point outside them. Latency would be terrible, but you could get the packets through eventually.
The cage may block avenues for that LAN's access to the Internet, but in the worst case scenario, someone could operate a sneakernet bridge by shuttling large storage devices between the wifi LAN inside the doors and the WAN access point outside them. Latency would be terrible, but you could get the packets through eventually.