I was at Petco today buying fish and I saw something similar. The young clerk sold 22 goldfish (feeders but for a tank, not food) to a woman without asking her any questions. When I asked to buy a dwarf gourami, he asked me what size tank I had and I told him. He was fine with me buying the fish and I thanked him for asking. He explained that he tries his best but that with some people it just pays not to ask what they are going to do with those fish.
That pretty much sums it up for me. I used to work in a small pet store back in my hometown and the ignorance of folks buying pets (including me at one time) can be overwhelming. And, how many of us have noticed that people will only hear what they want to?
Take this forum, for example. I don't know how many times I've seen someone post a question, get answers they didn't expect or want, and insist that those answers are wrong. They get all upset if they don't hear what they want to hear and most of them insist on doing whatever it was that everyone else advised against anyway.
The same thing goes with most folks in pet stores. I do think it would have been okay for him to ask her what size tank she was buying for and let her know that goldfish put out a lot of waste and get very, very large, but refusing to sell to her would have probably gotten him into trouble and maybe fired. It's not an easy job market out there these days in the US, especially where I live. I don't really blame the guy even if I did want to chase that woman down and wrestle the fish away from her.
Ah well.