The name is just a string, right? If some character in the string is causing havoc, maybe there is something funky going on. This is just one symptom coming up at the surface. It might require a bit of extra investigation to see what is really the underlying problem and if that might cause more and different symptoms elsewhere.

Interestingly, Wikipedia does give at least one example:

https://en.wikipedia.org/wiki/Equals_sign#Personal_names

When foreign names are written in Japanese there are a couple of ways of handling puncutation, and sometimes an equals sign is used. I hadn't actually thought about why it was used, but it seems an interpunct (・) is used where a space would be and equals can be used for an internal hyphen, or for words that are separated by a space but part of the same unit (de Niro).

I started a small company with a colon “:” in it. Should have not done that...

I regularly encounter services that does not handle it very well

You only need to run into one to make someone's life a PITA. Treat names as free strings, because there are a lot of names that do not conform to any notion of western normality.

Little Bobby Tables’ cousin, Jenny =true

> how many names do you run into with equal signs in them?

That's not the issue ... I have not personally tried this or examined it, it looks like you can change the state of the header parser by including interesting characters in your name. I am not sure if this is server-side or client-side. If the problem is server side, there is a chance you could tweak the strings to get interesting results. But trying to prove that this is a serious problem without explicit authorization will likely have adverse consequences for anyone who does, so only people who are already doing shady stuff explore it.

Whenever someone mistypes their hyphenated name with an =, say on their phone.