How the administrator enforce (html or text type of email in the user default settings

unknown

Hello team

I read that 

 An administrator can force the user to use a specific Email format by clicking the Apply link. The user will then be unable to edit this setting.

 

But i try it , i make the value (html) and i connect as user and i changed , so how the administrator enforce it , if i can change it manuallty ?

 

Regards

Nic Brough -Adaptavist-

You don't.  The type of email a user gets is up to them.  Html works for some people, plain text for others, the choice is (and should remain) theirs.