I recognize that it's way more culturally accepted with random conversations with strangers in the USA (something I really do appreciate with US culture whenever I have visited, BTW) than what I'm used to back home.
I don't think I've ever seen it happening in all my life over here. 99.9% of people will assume you're a creep/dangerously deranged individual and/or flat-out ignore you. There pretty much needs to be in a social context, preferably with alcohol, for people to accept being talked to by strangers.
Not that it should stop anyone from trying as I think it's a positive thing, but the barrier is a lot higher.