Users NEVER read on screen messages
Even today it's been my experience that users are incapable of reading the messages in the screen. I could retire today if I had a dollar for every time I've gotten a tech support call that could have been easily solved if the user had simply read the error message and followed the instructions it gave them.
For instance, we've got a system to track a certain subset of student goals. To load a particular student's data you have to have their student ID and be on the permissions list for that record. If you try to load a student who's not yet in the system you get an error message that says "This student is not yet in the system. You may create a record for them by entering their data manually and clicking save.' You would not believe how many calls I get from teachers trying to load data for students who aren't in the system.