If it's all about status, explain all the undergrads who send me "Yo wen is the homework due" as their entire email! Then again, these are the kind of people who think they're better than everyone else and their time is more important than mine and so on...
I've worked places where some people will only pay attention to what's posted on the wall and nothing else. Others will read only email and nothing else. Others will only talk or phone calls, and nothing else. Others will only do text messages, and nothing else, etc. You're probably always gonna have to expect some people to not care about email. When dealing with people who think it's your job to do whatever they want, maybe tell them "I only have one rule, ..." I only have one rule, I don't remind people about due dates.