Why did they ask me which college I attended when I entered Siam Paragon in Bangkok, Thailand?

I just walked into the building and somebody that didn't look like an employee to the place came up to me and asked me if I graduated from a college yet. I just shook my head and kept walking. A few days before this happened, I was also at Siam Paragon and by the escalators, a woman asked me the same question (but she asked, "Are you a student at Chulalongkorn University?"). I'm curious, they weren't selling anything so why did they ask me this question? They weren't doing a survey because they didn't have any papers or fliers (and like I said, they weren't employees either because they were dressed normally just like me). But they had to have a reason and I'm just trying to figure out what their motive was. Any and every bit of help is appreciated, thanks! FYI, I look Thai but speak English a lot better.