But I have absolutely no problem with haute cuisine restaurants doing this.
There's a few reasons that make this special, and in a completely different universe than being tracked online.
1. Most people, my wife and I included, seldom go to haute cuisine restaurants. When we do, it is a very special, once in a lifetime experience.
2. Restaurants are not staffed by hackers and advertising engineers. They are going to start with opt-in questionnaires that you will fill out when you make your reservation. That questionnaire will often come in one of two forms: a) they will just ask you verbally when you phone or b) they'll send you a package when you make your reservation. That package is usually pretty special unto itself. It's going to feel like a welcome package, and they are going to invite you to share anything that you think is helpful, entirely voluntarily. Typically they'll ask about food preferences and dietary restrictions... but I mean, they'll get a lot just by giving you a text field that asks "Are you celebrating a special occasion, or anything else you want to share?" You're free to put whatever you want in there, and leave anything else out.
3. Now we get to the social media part. This is doing a little bit extra above what most haute cuisines have done in the past. But remember - they can only find what you make public. They're not like, DM'ing people on your friends' lists etc. or hiring a private investigator to stalk you.
Once you're in the door, the idea of remembering that you were there before and jotting down your preferences etc. so that if you return they can make you feel even that more special... this isn't McDonald's, or even a fancy steak house, that we're talking about. This is a place that most people - if they go at all - are going to go ONCE. So people who return are extremely special and to show them that level of "we give a fuck about you" is what sets these restaurants apart.
One experience that my wife and I had was at Victoria & Albert's at Disney's Grand Floridian resort. We spent $2,000 on that meal. Why? Because it was our belated honeymoon. We were highschool sweethearts, got married and had kids really young and were extremely poor for most of our marriage... so we saved up and it was once in a lifetime. For that money... this level of service is a huge part of how they go above and beyond to make their patrons feel like it's worth it. If most people felt freaked out by it, that some personal boundary was being crossed ... it would be the last thing they do. But they realize that your typical dining experience is pretty impersonal. That if you're going to shell out that much money on a dinner... it needs to be more than just the world's best food.