Honestly it doesn't sound that bad on its own. Systems like this harvest very peripheral information and I think most people expect someone at the airports to be able to log and track their flight history if they've always flown with the same airline. Although even though you gave them the information a sudden "Happy Birthday/Anniversary could be very invasive feeling out of the blue (esp since that information alone tells the attendants nothing; the person might not want reminding that they are a year older; or they might have recently broken up!)
System like this tend to get scary when they integrate; attaching on other airlines is one thing; but when they then link to your facebook, your work log, your email and all the rest that's when it gets scary and creepy.
Meanwhile some people justifiably like to have a sense of anonymity . They don't have to be doing any thing wrong, they just don't like the idea of being watched all the time. Being spied upon, judged, evaluated, put into boxes etc... I could even see some arguing that such a system could lead to unfair preferential treatment (though in practice I doubt that would be the case and most likely it would just keep track of things like specific medical requirements *
*And if someone is noted as having a long term condition that might well be a life-saver. If the system knows Mr Blogs is highly allergic to peanuts, but forgot to mention it one time it would at least serve as a back up.
So there's positives and negatives; but the major issue is more when systems like this link up with others in daisy chain. Which considering how many big businesses often have multiple different companies under their belt, could be more likely to happen than people realise.
