That is kind of true. If you are on the sidewalk outside of a restaurant I *think* it's still considered their property. If they don't have tables outside of course no one will bother you from smoking/vaping/picking your nose outside in front of the establishment but if they have permits to seat people outside and have the seating out there then believe it or not the restaurants have jurisdiction over what they allow. For analog smokers you have to actually stand several feet from the outside tables according to some laws including in New York City. It is kind of tricky because obviously people who pass by and are not patrons of the restaurant can smoke while they walk by but if you're a patron of the restaurant you need to keep a clear distance. Not a lot of restaurants really adhere to this but I have encountered a few who do though. I was told even though I was outside the seating divider almost standing out by the street to move.
I don't want to get into the debate of ecigs being allowed because the above being said is about the jurisdication that restaurants have over their patrons. Granted the police may have attacked a different subject altogether but they may change their stance and just say that the OP was causing disorderly conduct which is well within their right to do.
I think if people are all out to raise awareness or to try and get away with vaping that they need to be clearer on laws and who has what jurisdiction while your on their premises. It's not only about laws it also about the rights of what the owners of these places have over you regardless if something is well within the law to do. A restaurant can simply ask you to leave if they think you are dressed inappropriately irregardless if you're sitting inside or outside or out of plain view. There is no law on how you should dress though is there? So the ecig applies here too, there is no law banning the use of it but if they want to ask you to leave and you don't listen and still do your thing it's perfectly legal for them to remove you.
Definately varies by city and state law as well.
I routinely smoke outside sonics at the tables around here in Texas, never had a complaint. I'm usually the only one at the tables though.