It is important for some snakes. In my experience and from what I've seen many other people post, all snakes handle things differently. I have some that could go without hides at all, and I have some that are still currently boycotting food because I changed 1 tiny thing in their tub. I'd say the behavior you have described sounds like she is stressed to some degree. If you have two identical hides on either side, they won't have to choose between security and safety. Also, I have yet to see you mention a thermostat...are you using a thermostat for your UTH?