The key to the dojo
I don't know how it works at your dojo, but at Windsong Dojo, there has always been a policy that everyone ranked shodan or above (or yudansha ) is given a key to the dojo. You see, there are no teachers assigned to teach given classes. Here, whichever person attending class that day has the highest rank by default leads that class. In many cases, that's usually the same person, but not always. And many times, the regular class leader won't be able to make it, which means someone else will have to run the show. And as long as a black belt is present, class can be held. So, rather than have a bunch of students standing around outside waiting for one or two people to show up, each black belt has a key to let everyone in. It's an amazing display of trust on the part of the dojo cho that, as far as I know, has yet to be broken or abused. The other week, we promoted a student to shodon in our morning aikido class. He now has a key, and being an early riser, no longer