Depends completely on the hotspot setup. Most of them block every single packet except DNS, until you have unlocked at which point you can do TCP or UDP. And DNS only passes packets out/in because it is a recursive function. As most hotspot setups are effectively NATs protocol-41 per definition won't work unless it is a rare NAT that forwards protocol-41 packets to the right host behind the NAT. Nevertheless, most of them, even after authentication, only allow TCP+UDP, there are quite a few which only allow HTTP/HTTPS over TCP for that matter.