From my point of view, I see it like this. In a perfect world, everyone on your team would have full map awareness, never fall for ganks, and CS like a boss. Sadly however, we don't live in such a world. People will die to obvious ganks, run off by themselves at crucial times, and trolololololol all the way home. The team that wins will most likely be the team that tries to reach communicate with each other more. You que up in a normal, you're putting yourself at the mercy of the intelligence of the people around you. I say, make it as easy as possible on them. Call MIAS. Place a ward or two for them so they can see the ganks coming. If you don't feel like baby sitting, I'd suggest getting four friends who want to que up for normals/ranked with you, 'cause otherwise you best get use to people *****ing about you not calling mias.
Just my two cents on the matter.