Well, if I assume the accepted 4 Gospels and the Acts of Apostles is an accurate account of God's son, then people got baptized as sure as they were sure they wanted to. I would imagine that could get abused by religions expecting people to get baptized right away without knowing about the cult they are joining. So I would say that people should know what they are getting into, but that would be their decision.
So if people wanted to get baptized into "the truth" (again, assuming there is a truth), it should be on them to decide when, just like the truth of the Biblical example shows. The religion should not expect them to know a long complicated doctrine, but the religion shouldn't expect them to go out in an organized recruiting work if they didn't want to, either.