Any time we walk outside with a cold, use your car, drive on less than 8 hours of sleep, or choose not to get a flu vaccine we put other people's health at risk

Any time we walk outside with a cold, use your car, drive on less than 8 hours of sleep, or choose not to get a flu vaccine we put other people's health at risk. We accept a certain level of risk to function as a society. If the acceptable threshold of risk was less than "possible threat to another person of any magnitude" we would be a very different society. It seems to me that we use a different rule to decide when to ban activities which is "good evidence of substantial amount of harm(drinking and driving, or second hand smoke)". I would argue that in order to ban e-cigarettes we need to wait for evidence that e-cigarettes are likely to cause significant harm to bystanders.