$()[0] == document // strange !?

$()[0] == document // strange !?


I just got bitten by an unexpected (for me at least) behaviour of the
jQuery() function:
$(), $(''), $(0), $(null) and $(undefined), all return a collection
equal to $(document).
...this causes weird things to happen when one converts a String to a
dom, when the string happens to be empty.
Somehow I expected
$('body').append( $(html) );
to be functionally equivalent to
$('body').append( html );
Is that an unreasonable expectation, and if not, is it too late to
fix?
--
Már