One Time Offers Showing More Than One Time

It seems that close to ever membership site is showing one time offers these days. As soon as you either log in or you leave a site, a one time offer appears before you. Some offers are really good, others are not so good. But what I think is both interesting and a little funny, is that many sites actually shows one time offers a lot more than one time. It says on the top of the page that you should read it carefully, because this offer will only be shown to you one time, and one time only. But in reality it will be shown to you over and over again. If the owners know this, why are they using the "one time offer text"? Is it because if presented with a one time offer, people are more likely to take action and buy it? I hope that this is not the case, I hope that people placing the one time offers on their sites thinks that it will only be shown one time. If they know that their visitors / members / customers will see it multiple times, then what they are really doing is lying and trying to "cheat". Do you agree with me? I don´t personally have a problem viewing the offers over and over again, but I get a little annoyed by the thought of being tricked into buying something.