Players might be able to penetrate the MOO's security
system accessing data and operations they do not normally
have permissions to read and manipulate, such as other players' mail and email addresses.
Even though email addresses are openly accessible at some MOOs, this does
not hold true for all MOOs.
There are also various ways for an
experienced MOOer to lag the MOO, or
even force the MOO to shut down for a short period of time.