A Cut Scene is an animation sequence that you - the player - has no control over. Most often, it involves only NPCs, but not always.
A tour is a cut scene where:
- you lose control of your character for a time
- your point of view is moved around the world.
- (often) some form of narration occurs while the tour continues.
Not all tours take complete control of your character away for the duration.
In some cases (such as the 'halaa bombing runs' in Nagrand, or the quest  , you have autonomy to use items in inventory during a tour. In the latter, you can even conduct combat.