When is a capture point being contested and when is being captured in Team Fortress 2? Whenever the announcer announces that a control point is being threatened by the other team, how is the determination made? It doesn't seem like there's much of a difference as there doesn't seem to be criteria for either. Is there a difference or is just random?
According to the TF2 wiki page on Control Point:
Control points are captured by standing on top of them.
If players from both teams are on the same, unlocked control point, that point is said to be contested, which means no progress is made toward the point changing team control.
So if you/your team are the only ones on the point, you will capture. A point is contested when both you and the enemy team are trying to capture the same point.
rosuav is correct. Although the wiki defines the terms "captured" and "contested", in actual gameplay the Administrator uses both words interchangeably regardless of whether any defenders are on the control point at the time the attackers walk onto it. It is completely random, and the game doesn't make any distinctions at all.
If a point is contested, it means that at least one of your own teammates is standing on the point at the same time as at least one enemy. In this case, the point can not be captured by the enemy until your teammate leaves the area or dies.
If a point is being captured, it means that at least one enemy stands on the point and makes progress towards capturing it for his team.