Forced camera locking

I am working on reconstructing, within Second Life, an experiment previously performed in a laboratory. Participants view an object from a specific angle, perform a mental task, and then make a decision. The experiment necessitates that participants only view the object from the predetermined angle.

The current plan is to have participants sit their avatars in a scripted chair. The script will then move the camera to the predetermined location of the object and set it to the proper viewing angle.

My question is, is it possible to forcibly lock someone's camera such that they cannot move or rotate it at all while they are seated in the scripted chair? (i.e. temporarily lock the participant out of using Focus/Orbit/Pan modes)

Not with the regular client. Theoretically, it should be possible to create a client that disabled user cam control, but it would be difficult to get anybody to agree to download and use it.

Thinking about this practically, a script could get PERMISSION_TRACK_CAMERA and use llGetCameraPos() and -Rot() to detect when the cam moved from the scripted orientation; then you could throw out those trials and admonish the subject to keep their mitts off the cam controls.

or you could make the object invisible by sending it a message when you detect that the camera has been moved by the subject. alternatively, you could rotate the object so that it is always seen from the same viewing angle.

or you could simply provide the viewer with an IMAGE of the object.

llSetCameraEyeOffset();
llSetCameraAtOffset();

Look into these it may help.
Forces a camera position that is currently free.
Remember that it must be set before the agent sits in the chair.

this also means that if there is a change in position, that the person must sit up and sit again.