[DGD] Letting the players code stuff

[Kurt Nordstrom]

Okay, so I'm back to playing with Melville again.  Yes, I know it is old
and not under current development.  I know it doesn't take full advantage
of DGD.  However, it is simple, and makes the most sense to my ex-Amylaar
mindset.  Phantasmal was awesome, but my brain is too full to fully grok
it right now.

So...I'm toying with the idea of a RP environment mud.  Sort of like what
people use a mux/mush for, but with code that doesn't look like line
noise.

One feature of mush/mux/moo is that players can, more or less, safely code
their own objects and commands.  This is something I'd like to allow.  My
thoughts run along these lines:

Rewire the security model to give editing permission to players within a
directory of their own.  Within this directory they could have a /cmds
subdirectory that they could use to write their own commands.  They could
also possibly code their own objects within their directory.

Since it is a roleplaying environment, and not a "Kill the monster, get
XP" sort of thing, the threat of them coding themselves a superweapon is
not so much a concern.  What is a concern is somebody coding something
that breaks the game or messes up the experience for other players.

Anybody have any ideas/considerations about how I'd go about doing this? 
Any caveats or pitfalls or what-the-hell-are-you-thinking's?