Good. It should be a problem for them.

If this becomes the trend (which in my opinon would be nice) it will become a big problem for companies that specialise in customer tracking e.g. for supermarkets and big department stores. Previously it was quite easy to track a customer, how long he or she spends time in the store, which floors he or she visits, etc. by putting up dummy WiFI-networks that the customers phones find by giving out their MAC-addresses.

I think on the general principle of privacy. But also, the idea that the more trackable you are, the more easily manipulated you are by marketers and advertisers. Free markets work better the more consumers are rational. Giving marketers deep psychological and behavioral insight increasingly enables them to circumvent rationality and "hack" consumers in various ways.