> I say blue for be in design with the prog, sure Red is more informative and preventive :)

Well, red is often times used as a type of warning. That's great if you are expecting a warning.

But if you don't know what it is that you are being warned about, or if the warning does not apply to you, then it can be confusing to see a warning... I really want to try to minimize this type of "confusion feeling" as much as possible.

That's why I would probably put it as an optional thing that you could turn on, rather than just showing some red surfaces to people by default.

- Michael