Best Practices for Storyline Player Controls

I am a big proponent of providing adult learners autonomy in their training and thus providing them open navigation as much as possible. This means not locking down the navigation pane, providing a seekbar that is not locked down, including next/submit buttons and previous buttons. The only thing I like to lock down is Knowledge Checks. I use variables to make it so that a learner does not accidentally jump to the Knowledge Checks prior to completing the learning portion of the training objective.