Foolmewunz
Grammar Resistance Leader, TLA Dictator
I know this wasn't directed to me, but:
A counter campaign, rather than a protest campaign.
If you want to help misinformation spread, draw attention to it by reactively protesting it.
If you want to stunt the spread of misinformation, spread information that crowds it out.
Make a website called vaccineswork.com and take out some provocative ads. Make anti-vaxxers react to you.
A counter-campaign would not be necessary if the anti-vaxxers weren't out there spreading their misinformation. Ergo, call it a counter or a protest, but the need is there only because they're spreading their lies.
I don't know why you feel that protesting is not viable, particularly in this instance. They've created a lovely focal point - Times Square - and are trying to get their lying message out in that location. What's wrong with raising a little ruckus and handing out the "counter" information at the same time?
If I was back in New York, I would've printed up some more appropriately-sourced information, and gotten an air horn and headed to Times Square. Every time the advert appeared, I'd have blasted the air horn and said, "If you want to believe that lying crap, it's your right, but here's some info from decidedly less biased sources than the snake oil this advert is peddling..." Or something to that effect.