Having developed may interfaces where color queues have been a requirement and being colorblind of the "red-green" variety (8% of males have some colorblind issue) I always insist on other mechanisms to highlight the issue. For instance Red on Black will totally disappear for me so a font change or other graphic change is required. Being an engineer I know that “color” an unreliable data source so I typically ignore ANY color as an indicator of a state change.