Fast forward to 2050

The year is 2050.
Yankele arrives at the gates. He tugs up at the navy blue sleeve of his school sweater, and flashes an armband at the metallic sign attached to the brick wall. A cryptographic protocol is deployed, Yankele and the school authenticate themselves, each verifies that the other is kosher, and that the kashrut certification was not revoked, or "cheremed", as the elders call it. The gates slide open, and Yankele is allowed into the hallowed sanctuaries of the Yeshiva day school. (The elders are rather proud of their two way authentication scheme. Before it was only possible to make sure the student is kosher, but what would happen if the school would rise in revolt, and overstep the proper boundaries? Now it's possible by one simple command to have the school shut down)
Inside the building Yankele stops to greet friends, both first checking that the other is kosher according to their families minhagim. Parents can program in permitted kosher associates for their children either individually, according to family, neighborhood, or even sect. (It's a very flexible system, and caters for all.)
Lessons are given by kosher and trustworthy teachers. The boys (girls would certainly not be considered kosher in school territory) then filter from the school yard and onto the surrounding streets.
Yankele heads home. He walks with eyes downcast. Occasionally he tentatively stretches his armband skyward, searching for kashrut certification . When a beep of approval is sounded, he lifts his head, to take in the rabinically certified poster or advertisement. (Eyes must be guarded at all times. The streets are still covered with pritzus, despite the elder's best efforts. )
A smell wafts through the air; meat roasting, chips frying. Yankele is hungry. He checks his armband (Which also conveniently serves as a watch, the elders thought of everything!). There is still time. He steps inside the take out restaurant, and purchases a cheese burger. He bites in, savoring the texture, and the taste. Finally an innocent pursuit, not requiring the rabbinical certifying board's stamp of approval.
Yankele's kosher certified phone rings, he pulls it out and flips it open. "Hi Mom, I'm on my way home, don't worry".
Passersby hear a once sided conversation, interrupted by chews and sips of coke.
"Oh, I stopped off for a snack on the way home"
"Where? In McDonalds. "
"Tatte? What's wrong Tatte?!"
"But I didn't know food had to be kosher too!"