I think you could use pause on lock assuming your PC locks when it goes to screensaver.
Windows key+L and the pc is locked in less than a second. =)
Although pause on lock would probably work pretty well in this situation, I actually think it would be a nice addition to foo_scheduler, to perform some event after xx HID idle time.
I might give it a try this weekend to see if it's possible.
Now if you can make a component that will auto-increase the volume when the blower fan for the A/C comes on, I might send you a batch of real cookies.
Is it possible or feasible to pause playback when the screen saver is active?
As foo_lock doesn't pause when (only) the screensaver hits, I like to mention that the component foo_AdvancedControls has an option to do it.
Thinking further of it, it would actually be cool if you had a program that could adjust output volume according the average noise from a microphone. Some car-stereos has the same feature which are quite useful to adjust volume automatically depending on how fast you drive. Could be a nice addition to a CarPC as well.