Most child custody questions have two answers: what is legal and what is best.

Legally, you have a right to hold the other parent to her visitation weekend -- assuming that this has been established in an agreement or by court order. This may not be what is best, however. Many experts agree that children benefit from maximum possible contact with both parents. So, it may be best for your child for you to be flexible regarding the weekend visits. Of course, if the visitation confusion happens often, the sheer inconvenience and uncertainty may require you to stand on your legal rights.

Turning now to your son who does not want to visit his mother: The legal answer is that you are responsible for complying with a judge's child custody and visitation order, which may on occasion mean doing something that feels like forcing the child into the car. But, again, this may not be what is best. Your child may have excellent reasons for not wanting to go -- and the visit may be detrimental to his best interests. If so, you may need to pony up the resources necessary to go back into court and ask for a modification, which may trigger a custody evaluation by the court.