I have the same question. I know teachers need to plan sometimes, but it would be cool to have the option to just have an unstructured chat. Teachers would have to opt in for this of course. The *option* is the operative word here. I'm sure teachers wouldn't mind more business, last-minute or not.

They also like their sleep. :) Seems as if there should be a mutual consent way to book sooner, but no. Too difficult to arrange.

You need to book giving 12 hours notice before a lesson. This is fair for the teachers as they need to plan their lesson.