When someone now logs in using the master key, the connection is not limited in any way by the authorization file. However, if the maid key is used, only connections from certain hosts will be allowed. And if the butler key is used, connections are denied from certain hosts, and additionally the allocation of tty is prevented. More information on the options (and command) keywords is available in the ssh2 man pages.
The per-user configuration directory can be changed by setting the UserConfigDirectory keyword in the sshd2_config file and on the client settings.
Per-user configuration information and encryption keys are by default stored in the .ssh2 subdirectory of each user's home directory.