I have also been told the same thing about night lights but I soon noticed that my oriental fire-bellied toads were very happy to hunt at night by infrared light (which I'd been assured they would perceive as darkness) so I have my doubts. I also think its dependent on the species as to which individuals are comfortable in low nighttime light. My North American Grey Treefrogs bounce around under infrared, but my African Reid frogs will not set foot outside their shelter at night unlesss the infrared is off, and both species are nocturnal.