Names beginning with "xml"

I meant to send this to the list, but by mistake sent it just to John.

Is a MicroXML document that

- invents its own xml:foo attribute or

- uses an existing xml:* attribute (say xml:space) in a way that does
not conform to the relevant XML-family spec (eg it says
xml:space="funky")

ok as far as MicroXML is concerned?

If so that compatible with the fact that eg xml:space="funky" is an
error according to XML 1.0?

James