[mindslight]

This was many years ago, so I don't remember the exact details besides it being one of those basic black plastic housing straight-through ones. I had been surprised because the quite-black electrical tape turned out to be seemingly transmissive. I probably solved the problem with something equally hacky, like sandwiching a piece of plain paper between the folded over tape, or perhaps a bit of metal.

If it blocked say 90% of IR, it would congruent with both of our points. I'll have to investigate further - it would make a much simpler ID mask.

(hm. Just did an experiment with two IR remotes and it did appear to block for the most part. One of the remotes worked really close up, but I can't easily rule out leakage or some other type of coupling.)