People should know that Lisp Machines do not have security.

[dlw at MIT-AI (Daniel L. Weinreb)]

All users of the Lisp Machine should be aware that the Lisp Machine
system does not maintain any form of security.  It is possible for other
users to spy on your terminal, crash your machine, and generally do
anything to your Lisp environment.  This message is not in response to
any problems anyone has reported (nobody has); this is just a warning to
help prevent any possible problems in the future.