In my life I have witnessed not less than 10 cases when the tactic of creating a sense of scarcity was used. I agree that it is rather effective, and nowadays it is used quite widely. Although, as a person who has been tricked into buying an unnecessary product with this very tactic and had some experience in this area, I can say that it is not completely flawless.
First of all, in order to use this technique effectively, a sales person must be a very good psychologist and know instantly whether or not it will work on a particular person. Because not always this is the tactic that will make a customer buy the product. Today people look for the things that are unique and one-of-a-kind, and saying, for example, that this is the last pair of shoes, for someone means that a lot of other people have already bought the same shoes and there’s no point in buying them because then you will be like everyone else.
Also, this trick might not work on the customers who have had some experience with it in the past. A person will recognize the same “trying-to-get-you-to-buy-it” lines in a heart beat and will be disappointed in that store or company and will lose their respect and loyalty towards them.
This tactic also backfires when you use it for a long time because eventually it gets too obvious. Plus, if some product does happen to be the last one and the store really has to sell it but it has been using this technique before, the customer might not believe you anymore.
So, like anything in marketing, the tactic of creating the sense of scarcity should be used wisely, in the right time and within