Currently we use U+2757 on forms to indicate that a form element is "advanced". This is problematic since that codepoint is part of emoji and displays differently on different devices.

In boost, we have this style:

.text-info, .highlight {

    color: #5bc0de!important;

}

Which is used to style the exclamation point. However if you view the forms on a phone it'll be red, since that's the colour that apple decided that emoji should be. It will look different on other phones too.

I don't see any reason why we can't just use a regular exclamation point.