As with most IR sensors, you are dependent on the field elements being somewhat opaque (it’s highly dependent on the sensors, the distances involved, and the surfaces). We found the Terabee Sensors to be robust on the field rockets due to the vinyl coating they had and we’d happily use them again. Beyond that, we tested them with polycarbonate in our lab and they worked shockingly well.
The main issue that kept us from using these during events was actually our design choices for our chassis and how we were resolving other problems we were having with mounting mechanisms. In particular, we did not account for the multiflex cables and should have made our mounting solution more robust for routing them… we have a small collection of broken cables now unfortunately.