Apparently my ISP (Cox) injects stuff as well? I've never seen this message before, but just now stumbled on it for the first time -- have been with them for 5+ years now, first time I've seen this message though.
Aside from the cap topic, it's outrageous to me that they find it OK to alter/inject into HTTP responses like this. Send me an email, sure -- but to alter responses?!
This is an issue with many, especially mobile, carriers... the key is to use HTTPS everywhere, and send issues/requests to sites not HTTPS to switch. Let's Encrypt removes the last reason why a site shouldn't be all HTTPS.
Note: fixing redirect rules for logins on some sites is a significant PITA, but should be adjusted accordingly by now anyway.
Just to be clear, this is a different kind of injection. Yours is at the visitor end (the ISP modifies the page while delivering it) while the original is at the server end (GoDaddy modifies the page while serving it).
https://imgur.com/a/f4BLf3h
Aside from the cap topic, it's outrageous to me that they find it OK to alter/inject into HTTP responses like this. Send me an email, sure -- but to alter responses?!