Exactly the point. There are those in every denomination who attend church, week in, week out, who believe that in so doing, they are saved. Nope. They might be saved as a result of going to church, after hearing a sermon that faithfully preaches the Gospel, or hearing a personal testimony, etc. But there is no salvation in the act itself, any more than being born into a 'Christian' community like the Amish makes you a Christian.
But when an Amish member sees the light and receives the free gift of salvation, they join the real Church - the only one that really matters. The one Jesus refers to in Mt. 16:18. And so it is with every denomination, including, I believe, all the unreformed branches of Christianity. Whether any members of cults are (or can be) saved, including one-man-bands like trapper, I leave to God. Only He knows the heart of the person.