Now it always returns 3, so either that module is buggy or it is a very unreliable hardware. But as I previously said, the device correctly turns on tvout when the cable is connected to a video input (and the desktop tvout applet correctly detects it), so it must be using some other way to detect that the video cable is connected.

On the other hand, thinking again about the on/off setting from a usability point of view, I think it should be removed from the control pannel applet, because it is redundant and very probably will cause problems because the semantics it implies.
Let me explain: the tvout is automatically turned on when the cable is connected, and off when it is disconnected, so no manual control is needed for it to work, and the only use of such control is to turn tvout off when the cable is connected, since turning it on with no cable is of no use. On the other hand, the on/off setting in the control panel, implies that the control is manual and one should set it at on for it to work.
That's what it happened to me, and I'm no noob. Now think what will happen if this is included as it is now in the CSSU and all those people who can't even manage to read the first post of a thread turn on tvout and start complaining of battery drain (me shudders).