I forgot to say that what you said is perfectly reasonable and not too different form my initial reaction. This is indeed very weird (but cool) science. :)
There is experiment to detect some sugars, that is somewhat similar to this alternative explanation (and unrelated to the experiment in the OP). More details in:
https://en.wikipedia.org/wiki/Tollens%27_reagent
Random quick video: https://www.youtube.com/watch?v=21PHoxlukME
NileRed video with more technical details: https://www.youtube.com/watch?v=nGmxHLHyUPc