Okay, I think I understand what you are saying. But, it sounds to me like what you are describing is that each LDS member prays for guidance regarding every individual teaching and revelation. Does that mean that if, after such prayer, you were simply convinced that the Spirit was leading you to reject that the Church is right about say celestial marriage (is that the right term?

) you could deny that publically without concern about backlash from the Church itself? Does that mean that the LDS Church doesn’t have any concept like heresy? Or excommunication regarding that?
The reason I ask is that if a Church has a teaching which it insists must be held it is claiming infallibility. Any teaching at all. If there is a doctrine that God is this, or that, and if you deny it then you are not eligible for this or that privilege then you are claiming some form of universal guarantee of truth. That is infallibility. It may be used often, or rarely, but it still fits the bill. If the LDS really do not believe in any infallibility within the Church then there really could be no results to disobedience or rejection of doctrines. I have a suspicion that you and Scriptorian may be using the word infallible with a slightly different meaning or intent than how we Catholics use the term.
Cothrige,
The LDS use the term “church” in several ways. There is an organization. There is a building. There is the “kingdom of God on earth.” The organization in its minutest detail is not infallible, because people are not infallible, including prophets. The direction of the Holy Spirit is infallible, but if people ask the wrong questions or do not ask enough questions or make decisions without asking any questions, even as church leaders, then the Holy Spirit will not impose God’s will. The Holy Spirit will let truth be figured out or found out when somebody is willing to ask the right probing questions.
The “kingdom of God on earth” will triumph absolutely, infallibly. People who are fallible will be a part of that process, making mistakes along the way. That does not make the “kingdom of God on earth” fallible–it means that people make mistakes and Christ redeems all of us if we are repentant and seeking to grow to be more like Him, and that He “uses” imperfect people to accomplish His purposes, which are perfect.
As to the breadth of belief allowed in the LDS church, I suppose the recent constitutional controversy in California is a good example. The leaders in SLC were very clear in supporting traditional marriage. Yet many members supported the opposite position in that case, for personal reasons. They weren’t criticized, ostracized, excommunicated, badgered, or made fun of. They could still go the temple–the highest form of worship in the LDS church.
But let’s suppose that an LDS member publically opposed the change in giving priesthood to blacks, and was asked to stop but continued to publically oppose it. Then that member might be denied a temple recommend, because of public opposition to an approved scriptural doctrine accepted by the church and unitedly approved by its leaders.
If I were to publically teach that polygamy was always wrong, and that Joseph Smith and Brigham Young were wrong to practice it, then I might be warned and eventually might not be allowed a temple recommend, but I don’t think I would be excommunicated.
Only a small percentage of the LDS ever practiced polygamy. Those who didn’t could still attend the temples and be fully participating members, though some leaders were specifically asked to practice it during the last half of the 1800’s.