> QUESTION: can you think of a value for the Altitude element 
> that the XSLT template would accept, but a schema validator 
> would reject? 

No.

 Can you think of a value for the Altitude 
> element that the XSLT template would reject, but a schema 
> validator would accept?


Yes. "   23   "

Michael Kay
http://www.saxonica.com/