Please do not do this. There are many disabled people that go to WDW for the accessibility including my boyfriend who uses a power wheelchair. I can get him out of the room if you start a fire with a candle, but quite doubt I would go back into the room to get his $12,000 chair out as well. Then you would have essential taken his freedom away.
It is pretty selfish to put 100's of people in jeopardy just because you want your room to smell pretty. Use air fresheners or plug ins. I don't think you should even use a candle warmer, I would think if it came into contact with paper etc, it would be a fire hazard too.