There is a lot of verification and supervision of OSM mappings, you would see it if you would follow any OSM forum.

What is a real problem in OSM is inconsistency. There are different styles of mapping, different way of mapping similar objects, and very different levels of details, depending on number of active users in a particular region. All this should improve, when number of data increases, like you can already see in some countries, where OSM mapping is very precise.