I’ve addressed this before, the issue of how some databases are not updated as well as they should be, and sometimes they have people listed as missing who have actually been found already. You might ask me: what do I make sure such cases don’t make their way onto my site?
The short answer would be “the best I can.”
Some databases are such serious offenders in this regard that I simply won’t list their cases at all unless I have independent proof that the person is still missing. (Lookin’ at you, New Mexico.) But I’ve learned the hard way that NO database is completely free of listings of “missing” people who were actually found months ago.
I also do things like check for active social media profiles. If a database has Mary Smith listed as missing for over a year, but Mary Smith has a personal Facebook page and it is definitely her and it definitely had recent activity, chances are Mary is not missing.
This is hardly a perfect way of going about it, but it generally works pretty well most of the time.