I've been using an IP radio at RV parks to get a strong connection to the wifi. I run it in router mode with NAT. I can get the splash page/captive portal to come up with the usual tricks but I recently found one RV park that had internet blocked using this setup. I can see they are using a Mikrotik router and, from what I can guess, using TTL to restrict the number of router hops. It's a simple firewall NAT rule - chain: prerouting, action: change TTL=1. The TTL default is something like 64 but with their main router to 1, none of the downstream routers will connect to the internet. Here is an example of the rule: https://www.youtube.com/watch?v=fKOaBMLcAWA

My radio gets an IP address and I can ping their router. I can see their DNS addresses but not ping them. The end result is the splash page won't load. I'm look for a way around this if it's possible. Not sure if bridge mode would count as a hop, but I'd also have to set the radio for client DHCP and figure out the IP address handed to it so I can login and manage it. And of course, have to deal with the MAC issue (for paid wifi that tracks by MAC).