We should disambiguate or flag users who set a displayname to match another's mxid

[matrixbot]

Created by @ matthew:matrix.org.

[ara4n]

Or worse, set their displayname to Matthew (@matthew:matrix/org) or similar.
An obvious bet might be to use different CSS on the disambiguated bit; by greying out the mxid a bit it would also look somewhat less ugly.

[pafcu]

I'd actually flag anything that looks like a mxid. E.g. greying out the disambiguated bit only works if you know that is supposed to happen and notice the difference. I can't think of any good reason to intentionally include a mxid in your display name at all (unless it really is your own), so that alone might be reason to show some warning to users.