many times its not a person not hitting the space bar,if everyone has the green "accepted" check mark, and it still says waiting on player, someone has a sub par computer, or their isp is having problems, and no amount of people telling everyone that the space bar is their friend is going to make any difference what so ever. so either get some patience, or suffer,those appear to be your only options at the moment
I notice this while duel boxing my slave computer is at bare bones Minamum reqs so when I space bar the main pc my slave pc is still loading the convo so in fact it does play a part on what some might consider not spacebaring. But in the whole scheme of things OP, man chill out and relax get off the high horse. Just need to have some patients.