it works like this
when you put in your mission its layed into the scripted
layer of the campaign
the units from the lnd layer
and the random layer of the campaign are layed in also
in the lnd layer (land) there are naval and air bases
with units available to dispatch to any contact within
a defined sphere
(put a base in your mission and go through the settings)
what it means is if your inrange of the base and get
detected they will dispatch units air or sea or both
to get you. plus the random layer units you may
come across.
the only real way to eliminate random units in your missions
is to just have your mission in and no campaign layers
I made my first mod to do this its called
MBFL mod (Mission builders Fast loader mod)
it takes out the campaign layers gets your mission working
with only units you put in it and drops mission loading time
to less than a minute in most cases.
it does however disable your campaign game while active
but jsgme puts back the layers unharmed when you deactivate
so you can still continue your career
its more a mission builders mod testers thing than a player thing
but it is fine to do single missions on as a player if you like
its available on my FF
here
http://hosted.filefront.com/MushMartin
and heres the release thread
http://www.subsim.com/radioroom/showthread.php?t=103633
Warning missions that came included with GWX 2.0 may not be
useable with MBFL as some of those missions utilize units from
the campaign layers
M