Such as RJ 45. I will have individuals who tell me that they want to have RJ 45 ends installed. If I did this by the book then they will not get what they wanted. They will get what they asked for. I could be a real pain, and have them sign a paper that this is what they want, then I could install it, then I could watch the customer freak out, and then I could point to the paper work as this is what they requested, and I can show them where to convert it to what they really want would cost an extra dollar amount to reinstall.
There is no such thing a DB-9. What they mean to ask for is a DE 9!
I know what you mean. Its unfortunate that most people are not well versed in proper terminology. Truth is you kind of have to take things with a grain of salt otherwise you will drive yourself nuts.