I think it should be made sure that in normal circumstances, branding copyright notice should be completely visible unless a fee is paid to hide/remove it. In cases where bottom floating widgets (e.g. CometChat) are used they cover all or most of the branding text. An increment in the bottom margin/padding of the footer block might help avoiding it. What about doing it in the shipped styles?
I think it would be "Tacky".
If you are able to "close" CometChat, it might not be against the rules.
If CometChat is hard to close or not very often closed, then it is against the spirit of Branding Violation.
I am in no way offending CometChat, it was just an example. Any such bottom floating widgets may cause this issue and there are numerous such widgets. If by default it is minimized and only expanded when needed then I am sure it will not be a violation, but in practice I have seen, usually such gadgets are kept expanded by default.