should ldm warn about multiple logins?

[Gavin McCullagh]

Hi,

it seems one or two of our users are logging in from multiple thin clients.
Any time I've done this, even temporarily, I immediately see bug-buddy pop
up as some evolution calendar component segfaults.  I'm sure also that
firefox, gnome, etc. are not happy for multiple sessions to run on one
profile.  Sometimes the earlier session is a dead one lying around,
sometimes the user has forgotten they had another login and sometimes they
just don't realise this is a bad idea. 

I wonder would it be possible to (perhaps optionally) have ldm

1. prompt for username/password
2. ssh in and check for existing sessions on the server
3. if another session exists give a warning and offer to either
   a. kill the existing session
   b. abort this session
   c. carry on regardless
4. ssh in and start session as normal.

I can put this in launchpad if it's realistic.  I'd just like a few
opinions on whether this is sane or silly first.

Gavin