Interesting tidbit about preordering: They claim to only bill when they ship a device, but ask for Credit Card information. Ergo they need to store cc information in clear text somewhere.
I could be wrong but I think some of the credit card tokenization models allow for billing at a later date. (as in, give the CC information now, receive a token, use that token later to charge)
Yes, many providers allow that (Stripe, Amazon, even Paypal)
I presume then that is how restaurants add tip to a credit card charge after returning it to the customer. I always used to wonder.
I think restaurants pre-authorize your card for some percentage over the actual tab, and then just capture the final amount including tips.