Absolutely. In the real world, there will be a variety of uses of
documents, and a variety of humans writing HTML in a variety of ways.
Many authors will probably start with existing HTML documents as templates.
Their most familiar tool will be their Web browser of choice. It is
unrealistic to expect hundreds of thousands (or millions) of document
authors to install and learn an SGML tool.
If we assume that most users of the Web are readers, not authors, then
it may make sense for browsers to do the best they can with bad HTML,
and not issue error messages. But that just says the default should
be that behavior; there's no reason why there couldn't be an option
that turns on error reporting.
/Rich Wiggins, CWIS Coordinator, Michigan State U