I believe hibernation is more of a choice than a requirement in captivity.

I'm sure there are people out there who will disagree with me on that one but it has always been a highly debated topic.
Even if you have no plans to hibernate your torts can still get the idea in their heads that winter is coming ... even inside! They take clues from the weather ... from what they may be able to tell from light patterns if they are near a window ... from the length of time since the last winter they experienced ... so, they know what to expect.
Even people who don't hibernate their turtles and keep them inside usually find that they slow down remarkably during the colder months.