requiring valid metadata

[Rod Widdowson]

> Thanks Scott. This seems pretty important. Maybe Rod could weigh in
> with an explanation?

I'll need to swap those neurons in (my head is deeply somewhere else).  We
did have an issue with V2 filter being easily spoofable - but I think that
was the ValidUntil _filter_ where it defaulted in the wrong way (fail if the
valid until date is past, but if there isn't one, that’s OK).

Poke me if I don't get back by week-end.