OK, let’s examine this: finishes that are light sensitive react to photons. It doesn’t matter if the lighting is direct sunlight, or light bulbs. Both produce photons But no doubt you know this, and I’m probably preaching to the choir.
We’re arguing about nothing. “Warranty doesn’t cover discoloration/fading” is pretty explicit and satisfies me; if it doesn’t satisfy both of us to the same degree, I suppose we can split hairs.
We completely agree that the guitar is better off cased. Most guitars are, for many reasons!
No doubt you’ve read the many thoughtful articles Bob Taylor has written about the need for guitars to be cased.
I suspect you’re a very sophisticated person who knows what’s what, and I won’t belabor the point. It’d be nice if guitars didn’t fade, but the laws of physics as they apply to certain organic pigments says they will, so what can a person do? I accept it as a possibility and try to do the best I can.
For me, that’s enough. For some who will only accept products with warning stickers, like the ones on car sun visors that drive me absolutely insane, perhaps it isn’t.