On the suggestion of Garet, I have implemented something called sleeplearning. This is option and works in the following way:
You type SLEEPLEARN followed by the number of lesson credits you wish to reach, and after you quit from Avalon, your character will remain active (but totally unreachable, not on WHO, etc) until that number of lesson credits is reached. Then it will become inactive. During this time you will be charged for playing Avalon at modem rates (i. e. 1 credit per hour).
If your sleeplearning is set to zero, as everybody's is, you will not use this facility.