I'm afraid that won't work. I'm sorry, I probably should have given more detail. The event works like this:
The player is on a boat in a river, racing eastward. The water in the river is slowly draining behind them. Currently, the camera pans from one side of the river to the other. The player sails their ship, trying to keep up with the camera. During certain dramatic moments the camera will change to show the event from a different angle, but the player still has control of the boat. The only problem is when they scroll around or if they hit F10 which stops the camera pan all together.
I might be able to use a dummy unit and lock on to that. Then I could move it as needed.
Anyway, if there is no simple solution I might try that.
If you loop the camera fast enough, it will override the attempts at side-scrolling. I wouldn't use lock camera because it has other bad side effects like locking the minimap. I think there also might be a command for this, but I am not sure. Isn't it in the player settings? If it is then there has to be a way to affect it with a trigger. Maybe Jass. It's above my pay grade if it is located there.
If you are using a timer you can call PanCameraToTimed(0x7FFFFFFF, 0x7FFFFFFF, 0x7FFFFFFF) just after you pan the camera (or apply a camera) and it wont let the player to move the camera.
The only way to move the camera in any way, is the drag the mag with the middle mouse button (they still cant zoom though).
I saw this here (tested it and it works like a charm).