No error about missing enctype="multipart/form-data" with input type="file"

Recently I found an error in my page, even though the validator checked
it as correct. This might be known or hard to check. But if it is not it
might be useful to put it on a TODO list somewhere.

In a form I used an input type="file" (inside a table). The form lacked
the enctype="multipart/form-data". I got no errormessage from the
validator. I noticed something was wrong because most browsers didn't
send the contents of the file, but the filename instead.

I think giving an error in this case might be helpful.

Thanks in advance,

Jan Willem Knopper

P.S. I am not a subscriber, but I'll check the lists.w3.org archive
pages the next few days.