I don't know about intentionally hidden doctrine but It seems to me that unlike the JW's, other religious groups wouldn't disown you or treat you as if you are dammed to destruction at Armageddon because you disagreed with a certain doctrine once you discovered it or understood it better. As far as I can see, they don't intervene in a persons relationship with god the way JW's do.
I can't imagine the leaders of any other religious group coming to the hospital to make sure one of their members didn't take a blood transfusion or reporting them after spotting them coming out of an R rated movie for example.