Marketing with Lies?

This weekend, some friends and I went to Santiago. Friday night we found ourselves in Bellavista, and as we were walking past a street corner, a man called out to us to inform us that we were specially invited to this club down the road, where there was an open bar for the next hour if we went right now. So we asked how many free drinks we would get exactly, which he replied with "1, 2, 3, 4, 5... however many you want!" So we agreed to go with him to this club, walked inside, and he directed us to the dining area first, because apparently we had to buy a meal in order to get the free drinks. We thought one chorillana would be fine, because we all love food, and an open bar was waiting for us on the other side of this plate. But then our server told us that we'd have to buy something else since one chorillana only covered 4 of the 6 of us. He then informed us that the number of free drinks depended on the amount of food we purchased, and that the open bar would only really last for another 20 minutes.
An experience like this makes it awfully difficult to trust restaurant and club promoters. They are only looking out for their own interest- which is to get paying customers in the building. In the states, in Des Moines at least, there are no street corner promoters, but it's also less common to see misleading promotions and deals. What you see is generally what you get. Here in Chile, though, I feel like they are always kind of trying to trick you, whether it's with an unmentioned covercharge or a string they forgot to say was attached. You have to be careful about which restaurants you trust, otherwise you'll end up paying $20 for an "open bar." (Which we didn't- we left. In a slight rage.)