[georgieporgie]

A properly coded IR signal from the transmitting 'disabler' device could still be picked up by the iPhone even if it was severely attenuated.

How about IR filter + 555 timer connected to an IR LED near the camera lens. Filter down the unwanted IR signal, then wash it away with a flood of intermittent IR of your own.

At ~30fps, you can quickly get 100+ samples to cross-correlate with to search for the encoded 'disable' signal.

Can you explain how that works? I don't have a deep grasp of CCDs, so I don't understand how a signal like this could be encoded within a single 1/30 second frame. I thought that all pixels were captured simultaneously, is that not the case?

[wnight]

No, they simply mean that you quickly gather many whole frames and even if the signal is mostly lost in most of them, enough would remain.