I have a feeling vaping will win the battle. There is no logical evidence to ban e-cigarettes, maybe possibly to regulate it by the FDA or even Big Tobacco, but that won't happen for years to come imho.
I've vaped in countless hotels and I have never had any issues, especially with the smoke detector. The odorless vapor vanishes in less than seconds and for all they know, it could just be steaming water. Vape with confidence!