I actually end up doing quite a bit of improvised outreach with Jacko to little kids seeing as one of the spots to rest along our walking route happens to be the community centre where all the daycamp kids come back to so their parents can pick them up.
The kids of course are very fascinated by her BUT i'm quick to tell them they cannot touch her because she is shy and I don't want her or them to get scared or hurt. I find it works with your average person when you put it into terms they can get. If I was talking to the kids for example, I'd say to imagine how they felt if someone they didn't know came up and hugged them without asking and say they'd probably yell at me to go away or try to push me away because they wouldn't like it or be scared. I then say that because Jacko can't talk that her way of trying to protect herself when she's scared is to bite.
At that point, everyone gets the message and they spend most of the time trying to get her to talk or asking me if she can fly or what she eats or how old she is (or how i know she's about to poop

).
I agree that a socialized bird is a must---and Jacko I think actually enjoys getting accustomed to all these little kids and etc around her. HOWEVER, I do NOT agree that a bird must be able to be passed around like a hot potato. If anything I'd say expecting that is demeaning and a little insulting to a sensitive prey animal like a bird---this is where we must remember they aren't dogs who generally if well-socialized love most people they meet and like petting. How many people would enjoy being forced to hug any stranger that asked for it?
Thus, I think expecting a bird to interact with and step-up onto or make itself vulnerable to someone it does not know well is not respecting the bird. A parrot should be allowed to know and form many trusting bonds with people it knows well---and should be used to being handled by said people. For complete strangers? Give them a treat to feed to the bird OR if you know 100% that your bird likes to be handled by new people and cuddled by new people then let the bird take the lead and only show the person rudimentary he-likes-to-step-onto-a-hand-held-like-this. But generally speaking with sensitive animals inexperienced people should keep hands off, unless the animal is of the temperament to be a teacher. Much like with horses...you wouldn't put a beginner on or let them handle a horse that wasn't so easy going, dead-broke and patient that it was almost happy to teach them what to do---and even then with guidance of someone else much more experienced. Same with parrots I think.