Airport Wifi
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.