You summon someone ...

c su tamaz;k tamaz  (Yeah, right, who in their right mind?!)
Your eyes glow bright purple for a moment.
Tamaz arrives suddenly.
Tamaz's body flickers with green energy.
Tamaz disappears.
They aren't here.

This is very frustrating.   But it's NOT as frustrating as when it is 
IMPOSSIBLE to summone someone, because that person is fighting.
Well, this is quite reasonable, but in ONE instance ... when someone 
is in their clan room ... and everyone knows that clan rooms are not 
readily accessible to others.

So, what could be done about this?
Simple:  A flag added to the rooms, whereas, even IF you had your 
fight prompt or whatever, you COULD be summoned while you were in 
your CLAN ROOM.

This would stop people from mindlessly stance-training (BOTTING!!!) 
away inside their clan rooms, and would also prevent people's HIDING 
and avoiding pk by stance-training.  Yes, I'm sure all of  us have 
seen that bull crap at one time or another, where your gm all prey 
goes and stance-trains while you desire to hunt them.

And, hey, if they want to stance-train and don't want to be summoned, 
they can choose a remote location on the mud. ... I remember when I 
was a newbie vampire, and the clan that I chose did not have a 
clanroom at the time ... so I did not have the crutch of stance-
training inside a clan room ... one had to brave the big, bad 
outdoors.

Instant
