Grammar Nazi

Being an English teacher and a writing tutor have turned me into quite the little Grammar Nazi. I cringe when I see blatant semicolon abuse and am astonished at the fact that some people think you can capitalize any word you want to. Perhaps one of the most baffling grammar issues to me is what I call the "church command." You will notice that at church when the song leader wants the congregation to stand they will say something to the effect of, "Please be standing." What kind of grammar construction is that?! Who says that in the real world? When you want someone to give leave, you don't say "Be leaving." When you want someone to stop, you don't say, "Be stopping." If I break it down in technical terms, the "church command" as I call it is the infinitive "be" + the progressive. It's like a whacked out present progressive, but it acts as a command. I don't understand this. So if you hear me moan or snicker when the songleader asks us to "please be standing," now you'll know why...