One of our clients was building a form and noticed that one of the fields (a radio button field) was displayed strangely. The field appeared more to the left than the other fields and the text and radio buttons were overlapping.

I realized that this was because the user had set a CSS Class on the field named "radio" which appears to be a class already used in Forms somewhere.

Are there other classes that are "reserved" like this?

Can there be some sort of built-in warning if the user tries to use one of these classes?