Publish date was implemented the summer of 2005, so that is not an option. However, ignoring hidden dates before the geocaching started could definitely be an option. Though I would prefer that Groundspeak actually took responsibility for their data and corrected things that obviously are wrong. But on the other hand, the canister could actually be hidden in 90s (with another purpose), but published 10 years later.
I have added a date requirement of 2000-01-01 or newer in the development environment now.