That's an interesting thought.

On some forums you see, there's a warning bar beneath the member's name. They get one warning (1st bit), then the second offence is a temp ban and another bit filled on the warning bar, then a 2nd warning (3rd bit), a longer temp ban (4th bit), and then a Perm Ban for their 5th offence (full bar).

Then at least people do get a warning for doing something against the rules, and know that what they did was wrong. Because maybe when they did it they didn't know what they were doing was wrong.