I look at prestige only as a loose guide to potentially how big of an army a person has. It is impossible for a low prestige player, say with just 100k or 200k prestige to have 500k archers and 500k cavs.
Although it is possible for a low prestige player to be a noob, it's also possible that he's very experienced on another server and is just starting a new account on another server. We recently took on a few members in our alliance who had close to zero prestige, but they sent me mail and explained their situation.