Rather than all these bans, how about this: If you use your cell phone in an irresponsible manner, you will be subject to a fine -- anywhere, doing anything. For instance, an example that happens to me four or more times a week -- you are walking down the street while texting and you are not looking up at all to see what's in front of you, until the point where, due to narrow sidewalk or large crowds, I have no way to avoid you and I am forced to say out loud, "Watch where you're going." A cop who witnesses such a moment should be able to issue you a citation, even though you are pedestrian. Maybe then people will learn to watch where they are going. Also, if you cause an accident of any kind because you are using your cell phone irresponsibly, whatever insurance policy you have covering the accident will be voided and you will lose the ability to defend against lawsuits for damages, i.e. full and automatic liability due to irresponsible behavior. If the accident you cause due to your fully cognizant decision not to pay attention causes someone else's death or serious injury, you face the same manslaughter charges you would if you were, say, driving drunk.
And in regards to overindulgence with junk food, which would be better -- to ban super-big drink sizes, or to open the restaurant and food industries to the same tort liability that the tobacco industry faced? I'd be good with either.
People can either be nannied, or they can be responsible adults. Responsible adults suffer the consequences of their bad decisions. Which sounds like more fun -- nannying or responsibility? Because having neither should not be an option.