The only time I've seen charging ports available is at airports. I've never seen them at restaurants, or other places commonly frequented. While it may be convenient for the guests that need at is a small percentage (10-20%, I guess) for a large investment ($2-3,000) and maintenance ($200-300 per month) on a technology with a limited lifespan. Plus, my experience with restaurants is that you want to get people in, ordered, and out in as little time as possible. Table turnover means $$$, and people sitting at tables not ordering is a drain on profits, as you have to keep people there to take care of them, should they order something, which is a good thing, but people don't tend to order much after their initial meal.
For shopping, who wants to set their phone down and then shop, and forget it?
I guess what I'm saying is that your solution is good, but a better one may be a USB port so that people can use their wireless puck, micro-USB, lightning cords and put the onus of charging on them. There's a reason why we still use waiters instead of a computer and food servers at restaurants. It's simply easier and cheaper to have a person do all that work.
I don't want to come down as a nay-sayer, but I have a couple of patents in the works, and the review process to do this is like a "why would anyone want to do this?" on steroids. If you're 1/3 with idea -> patent, you're like a Major League Baseball player with a 333 average.
