Many “free” wifi hotspots give you a limited time per computer. If you’re traveling light and forgot to bring extra devices, it’s easy to give a Linux laptop multiple personalities:
$ ip link 1: lo 2: wlp4s0 3: enp0s25 $ ip link set dev wlp4s0 down $ macchanger -r wlp4s0 $ ip link set dev wlp4s0 up
... And then connect to the wifi and jump through its silly captive portal hoops again!
Changing your MAC address occasionally can be part of a healthy security diet, making your device slightly more difficult to track, as well.