I've got approached by people saying that I'm not allowed to fly many times. Mainly I think that happens because sometimes I decide to fly from a pretty strange location, for example I take off just from a beach (hand launching), or near a street with people. Yes, it is legal in Spain before anyone tries to say that I'm breaking the laws, flying over people (but not over groups of people) is legal in Spain.
I don't care much about people approaching me, some people here said that they fly from a hidden location or similar, I don't like that because it looks shady. When someone approaches me, I handle it differently depending on if the person approaching me is calm and respectful or not. And I can say from my experience, most people who approach you for drone flying, are not very respectful. Two people already claimed I'm spying on them (which is obviously not true).
But I also had some people approaching that were chill, for example, the other day a guy approached just I have landed my drone in my hand near a beach and said respectfully that I might not be allowed to fly there, he just wanted to warn me so I didn't have any problems, that's what he said. I was actually allowed to fly there, and what he probably meant is that I'm not allowed to fly over people, but in Spain it is allowed. I didn't want to argue, just said “Thanks for the advice, but I'm flying legally and will not have any issues with anyone” and he just walked away. Also, a handful of people asked about my drone, how does it fly, and the specs.