i keep my darts in the same room as my other reptiles. I keep a red light on at night for me to see my snakes and geckos. They can not see the red night light, but can my frogs see it?
I would not discount that amphibians can see under red light as they exhibit an unusual response to light, both by spectra and intensity. For more details see Duellman and Trueb and/or Amphibian Biology by Heatwole.
I think Derek was agreeing with you. When I read the post the second time, it seems his observation agrees with what you are saying. Being noctural, the Phyllomedusa would sleep longer into the night under the red light (we can only assume because they 'saw'/ 'felt' it). From his post I gather he now uses the 'moon' bulb with different results.