Probably high levels of EMF are dangerous as a cellular level and there are studies which "suggest" this is true. I'm not aware of any studies done at the still relatively low levels being emmited by devices like hybrid/electric cars or cell phones.
Probably you best bet on deciding how to act is to look at the cell phone scare of a few years ago, where one or two people devoloped cancers close to where they normally held their phone to the head. After those reports, many people started complainin of headaches and other ailments. A few years later, and no one talks about it any more because no research could link any significant risk to phones. I suspect there is already research being done by credible universities on EMF levels and cell damage. Keep an eye out for links to reports in major medical publications. If they ever put something out, it will be more specific about levels of risk and then you can make a good judgement, assuming there are any non-hybrids/electrics by that time.

I suspect your more likely to be "damaged" by worrying about it, then they are actually being "exposed" to it. If there are any risks, they would almost certainly be offset by the reduction of fumes they are exposed to. You didn't mention your age, but how long ago was it that none of us wore seatbelts and would hop from the front to the back. Sure there was additional risk, and lives were lost, but most of us lived on and are now that much more aware.

I just reread this....I don't know if I helped or harmed...sorry.