Let me play devil's advocate here. Users who are not tech-savvy or those who are new to using credit cards online might be afraid at each step that they do some

Let me play devil's advocate here. Users who are not tech-savvy or those who are new to using credit cards online might be afraid at each step that they do something wrong. -Enter credit card! -Uhm, I wonder if it means with spaces or with dashes or just the numbers, I hope the money won't go to the wrong place If it says 'no dashes or spaces' at least it's clear and might be reassuring to the user that the designers have thought of the same thing as him/her, which sort of indicates that he/she is on the right track and hasn't screwed up yet. I'm not saying this is good usability practice, but it would be interesting to test different versions for user reactions.