Common scams in Dubai

I have experienced a scam in naif road near Baniyas metro, i was just walking on the road a men came to me and asked me from long  are you wearing spectacle ? without knowing his intention and since he seemed to be friendly i told him from last few years then he said actually the eyes problems r very minor one which can be corrected within few days with some traditional medicines, and he just want your prayer for him and his family in return nothing else he is not expecting, not  even a single penny, once you hear this, u will completely trust him, as his intention looks good, once you agree he will take you to a shop nearby, which looks like a small grocery selling traditional medicines, now the real game starts, he will order some medicines without asking the price neither asking you and the shopkeeper will give all what he asks and say the cost is around 200 to 300 AED, and you cannot say no because some medicines they give his from bark of of some tree which he will break and make powder in front of you, and he will he cannot reuse it or sell and he will become aggressive saying why can’t you guys decide before buying, so you do not have any other choice except buying it, finally once you pay without any choice, later you will understand the shopkeeper and the man who fooled you are a team, be aware, not only spectacles, they will scan your whole body while you are walking on the road, and if you have any moles on face, rash etc any kind this will be the same game plan they will use