The vncserver initscript is bad:

- if you start it more than once, it starts more than one vncserver
- if you stop it, it stops _all_ vncservers, even ones that it didn't start

I think that a nicer way of doing it would be to add this to
/etc/X11/xdm/Xservers:

# Uncomment the following line to have a VNC server start automatically
# :1 local /usr/bin/Xvnc :1 -localhost