See, not all "errors" are unintentional, including language errors. Most of us have seen or heard criticism of the redundant "free gift" offer made in various promotions. My friends, Mr. Barnes and Mr. Noble emailed me today to offer me a free gift if I get one of their credit cards. (We're very close friends; they email me every week about what they are up to at work. I email them back about what I'm doing that week also.) There is a high level of "freeness" associated with the word "gift" (see def. #2). The alert level of freeness in gift is, in fact, at red. Everyone knows that, including Messers. Barnes and Noble. They also know that if they offer me a "gift", I will subconciously know it's a euphemism for "not a gift". So companies tack on the word "free' because it still has the Pavlovian power to make us salivate, or at least read their offers ("Made you look, made you look, made you buy an on-sale book!"). I believe, though, that that word "free" is losing its effect. Soon they will have to offer a complimentary free gift, then a gratuitous complimentary free gift.
Words and sentence structure impart messages to us. "Free gift! We'll give you a travel mug when you sign up for B&N credit card!" says "Look! Pretty! Shiny! Travel mug! Can hold COFFEE. Don't look at the nasty, evil credit card; look at the shiny object! You want it." Why don't they change the ad to say, "We'll give you a pretty, smooth, plastic card if you take one of these old travel mugs off our hands." Make it seem like a status symbol, the way American Express does. People PAY to have an AMEX card. No free gifts for them. People with AMEX cards can buy their own gifts.
(By the way, I know "freeness" is not a word. I sometimes intentionally misuse language. You should assume that any language, grammar or spelling errors you see in this blog are intentional.)