Re: C.4 Undeclared entities?

OK, I'll bite.  David is merely the last in a moderately long list
(i.e. at least three people :-) who have asserted without any argument
that "users won't include a <!DOCTYPE ...>, so we shouldn't require
one for well-formedness."  I have to say I just don't get it -- why
ever not?  They're going to have to do a lot of other, more
substantial, things differently from what they are used to, if they
are hope-to-die HTML mavens, who are the only group I can suppose
David et al. have in mind.  After all, both SGML fans and total
newbies won't have any problem with following this rule.  Why is it
likely that HTML fans, who after all have at least HEARD of
<!DOCTYPE ...>, will ignore this requirement but not, say, the
requirement to provide explicit end tags?  Or the requirement to quote
all attribute values?  Seems modest by comparison, and a small price
to pay for SGML compatibility.