This fun fact gets even more fun when you consider that a human radiates a nonzero amount of visible light via blackbody radiation - on the order of a photon/minute - which means that in theory, with some luck, in an otherwise cold and completely dark room, two humans might be able to notice each other through vision alone.
You can check my math here if you want to convince yourself: https://www.spectralcalc.com/blackbody_calculator/blackbody....