example.com is good because it is explicitly reserved for this purpose and has no MX records.
Although very occasionally a service will check for MX records, but that is incredibly uncommon. My go-to email for public WiFi is fuckoff@exmaple.com and have only been denied once (<1%)
A fair number of places will deny that, but I like to think it sends a message. I'm not sure how many, if any, domains still have a working webmaster@ address though.
Although very occasionally a service will check for MX records, but that is incredibly uncommon. My go-to email for public WiFi is fuckoff@exmaple.com and have only been denied once (<1%)