I have been in any number of quorums or wards where a local leader thinks that their calling as a local leader thinks they can simply assign people to be at certain places at certain times at will. They think that is how the priesthood operates. Now, the best full talk on the matter is Boyd K Packers "Parents in Zion" but a quote that hits the nub of the matter quite perfectly in very few words is from Joseph Smith
"The matter of consecration must be done by the mutual consent of both parties; for to give the Bishop power to say how much every man shall have, and he be obliged to comply with the Bishop's judgment, is giving to the Bishop more power than a king has; and, upon the other hand, to let every man say how much he needs, and the Bishop be obliged to comply with his judgment, is to throw Zion into confusion, and make a slave of the Bishop. The fact is, there must be a balance or equilibrium of power, between the Bishop and the people; and thus harmony and good-will may be preserved among you." - Teachings of the Prophet Joseph Smith page 23.
The same is true for consecration of time as it is for consecration of property. To give the Bishop power to say exactly when everyone will be where and he be obliged to comply with the Bishop's judgment is giving to the Bishop more power than a king has. There must be a balance, or equilibrium, between the Bishop and the people; and thus harmony and good will may be preserved among us.
That being said, it is worth going over Elder Packers talk, which gives a much more detailed description of the relationship between family, church service, and callings.