Only way that I can think of doing that is to have the following at multiple locations
Code:
if (%quietbot) { .halt }


You'd have to put that in your script every location where you want the variable checked.

On the other hand, if you wanted a script to not execute if %quietbot = 1, then you could use
Code:
if (%quietbot) { .disable <group name> }


Just make sure that all of your scripts have group names. You can have more than one group to a script, but you can't have a group within a group.

Groups start with a group name in the format #<name> on
and end with #<name> end

When a group is enabled, the first line will read #<name> on
When a group is disabled, the first line will read #<name> off