AUK, the problem with Africa is that you never know which kind of experience you are going to have ...
It might be the, "Hey, who cares, everyone can go through." or the "No one goes through until they show me their papers. Twice" or "No one goes through until they have given me their papers - those nice green ones from America" and so on.
Also, each country in Africa is not consistent, you cannot rely upon their being one cultural attitude to queuing and so forth. The main factor that you have to include in Africa is simple. Time, lots and lots of time. Be patient and don't lose your rag. OK, that goes for most places of course but Africa really does have it's own tune.