Yeah there definitely would be attacks where they use long fake domains if the site decides to hide the domain once it gets past a certain point
e.g president.whitehouse.gov.us[hover to reveal the rest]
But if it's always fully displayed then it's not really an issue. People could make fake accounts anyway under the current system. If you can't tell @elonmusklet93902398098 isn't really elon musk then I don't know what you expect to fix that.
The important point of this feature is that you know tim.wang.com is really an employee of wang.com and not just a rando. You know he really comes from that address so you could follow all the wang subdomains and know only real wangers will be followed.
e.g president.whitehouse.gov.us[hover to reveal the rest]
But if it's always fully displayed then it's not really an issue. People could make fake accounts anyway under the current system. If you can't tell @elonmusklet93902398098 isn't really elon musk then I don't know what you expect to fix that.
The important point of this feature is that you know tim.wang.com is really an employee of wang.com and not just a rando. You know he really comes from that address so you could follow all the wang subdomains and know only real wangers will be followed.