Haha, I guess the security guards can get a little bit weird at times! I think something similar like this happened to me as well. I was like 11 years old and I went to the shop. I wanted to buy some sweets but I didn't have a lot of money, so I was limited to the options. I simply couldn't pick what I wanted, so I continuously walked around the shop for like 30 minutes without picking anything. After a while, I noticed that every worker in the shop was staring at me and talking to each other. Then, even a security guard started to follow me around from a distance. Gosh, I was scared back then, so I picked up some chocolate and went to pay for it... Never did I spend more than 5 minutes wondering around a shop :D
Hehe that is a lesson well learned!