If I walk into a bar and order a drink I expect them to ask for ID to prove my age. If I walk into a McDonalds and buy a Big Mac I would not expect them to ask for ID to check my age and if they did I would not expect them to photocopy it and give it to Fred to keep in his poorly locked file cabinet.
@grumpygamer
Instead of copying your ID, can't Fred, knowing you are you, and old enough to buy and consume that Big Mac, issue you with a unique, but otherwise random code, not linked to you, but verified in person, which you could also use in Wendy's or Taco Bell? They will know you are a suitable patron, so you can have BBQ Bacon Melt, Big Mac or Volcano Burrito as you prefer, and no-one needs to compromise your Id. (I know some people can"t get to a restaurant but the principle stands)