Here's how it should work: if there aren't yet two people in your group standing by the meeting stone, everyone in the group should be running, riding, or flying to get there. But of course that's not what really happens-- what happens is that the leader of the group makes it there first, and everyone else continues grinding, or goes to check the AH one more time, or has to run repair, or finish a BG, or any number of things that don't involve getting to the meeting stone and summoning. Worst case scenario is that people start trying to convince others to go for them, and one guy is left at the meeting stone shaking his head.
Now, some people say that whoever made the group should be summoning, and in most cases, that seems like a good idea. But there are always exceptions. Even if I'm the last to enter a group, I usually start making my way towards the instance anyway-- the trip is never that long, no matter which instance you're going to, and it's better to be nice and use the flight to get another beer/soda then to sit around demanding a summon.
Unfortunately, there's no real way to fix this except to call out people for just plain being lazy. I guess it would be cool if Blizzard gave a nice timed buff to the first two people in a group to use a meeting stone summon, except then you'd probably have tons of people hanging around the RFC meeting stone in Org before they queued up for the battleground. As a few people point out in the thread, probably the best way to deal with it is just to give up on the group. Maybe next time they'll be ready to work together outside the portal as well as inside.