> they have a right to have their name spelled correctly

IMO, having the law consider this as an unconditional right is the root of the problem. What happens when people start making up their own characters that aren't in Unicode to put in their names?

> Also it's not nice and bad for business to be like this.

What about having a validated "legal name" for everything official and an unvalidated "display name" that's only ever parroted back to the person who entered it?

> What happens when people start making up their own characters that aren't in Unicode to put in their names?

They first have to fight the Unicode committee and maybe they actually have a point and the character is made up in a way that is acceptable in a society. Then they will fight their local authorities who run everything on 30 years old system. Only after they become your problem, at which point you fix your cursed regexp.

>an unvalidated "display name" that's only ever parroted back to the person who entered it?

You will do that wrong too. When you send me an email, I would expect my name to be in different form compared to what you display in the active user widget.

The point is, you need to know the exact context in which the name is used and also communicate it to me so I can tell you the right thing to display.