As with most things, it all depends on the snake. In general, lights are stressful because they are nocturnal and in most cases it can cause stressed behavior (off feed, roaming, etc). But, some tolerate things better than others. I have some that it probably wouldn't effect like yours', but I have some that would all out boycott food if I put a light in their enclosures. It's more of a general thing, not a fact as it doesn't apply to all.