Region 0 doesn't mean it is a fake, it just means it is region 0.
There are loads of genuine region 0 DVDs, they are mainly children's educational DVDs, old TV series and low budget films that have been re-released on DVD
I think the reason they are made in region 0 is because they are unlikely to be hot sellers, and the DVD producers just can't be bothered with the extra hassle of creating different stock for each region.