Honestly, I wouldn't eat at a sit down restaurant at all if it weren't for mystery shopping. I don't enjoy it, I never have. I've yet to experience one of those QR code menu things, hopefully I won't have to. I DO have my phone with me, but I was raised before cell phones, and while it's always with me, I'd be just as happy to leave the forking thing in my wallet.. But I'm also very conscious of folks near my table, especially servers and managers. When I see them coming, or when my son does, we both say something, and put our phones face down on the table. Holding your phone, looking at your phone, and not paying attention to the people who are trying to feed you and make you happy is just plain rude, and I don't like when snotty rotten little kids do it to me. It does piss me off when I see my server standing somewhere in the restaurant, even if they aren't very busy, looking at their phones while they are working.
As a mechanic when cell phones were new, we were told to leave them in our cars, or that we couldn't use them while we were at work, except at lunch, and not even on our 15 minute break time (union fleet service) because that was "company time." But that all changed, everybody got used to cell phones being everywhere all of the time. And the last 15 years of my career we were expected to have a phone, that the company didn't pay for, so that we could coordinate with the shop while we were out picking up vehicles for service, or taking the warranty jobs to the dealerships, or broken down because of idiot phone technicians not telling us what was really wrong with the trucks when they sent in a repair ticket.