Thanks.
You would be surprised to know the amount of validation work done on CB. It's not hours or days, but weeks... So this small inline CSS flag was a forgetting more than
The CB forms (registration and user edit) itself don't validate XHTML 1.0 trans yet, because it uses a private attribute, but which doesn't interfer with browsers, as it's standardized that unknown parameters should be ignored
This is historical stuff (you maybe don't know that CB has been around even before Mambo 4.5.0, years back), and the validation and fields part will be rewritten completely in one of the next 2 releases.
We have taken the decision to stabilize, and not to rewrite that sensitive part between RC2 and 1.0 stable, in order to get 1.0 stable out without a RC3.