by setting fast_logon=true in the [login] section of the ctrl/modopts.ini file.
A user can choose a fast logon by prefixing their user name or number with
'!' (configurable via 'fast_logon_char'). This option tells logon.js to
skip the logon menus and logon events.
The logon.js just looks for bbs.fast_logon==true, so if you have your own
method of detecting a fast logon (e.g. a logon matrix menu or a prompt of the
user), then you could just set bbs.fast_logon=true and continue to use the
stock logon.js.

Other ideas (not implemented):
- a minimum security level (or ARS) required to allow fast logons
- a notice to the user that fast logons are available (enabled)
- option to skip logon menus but not logon events, or vice-versa