Yes, you set options to leave devices on. Make sure you
use discrete on and discrete off rather than power toogle
if available for your devices too. Then when you shut
down your viewing for the evening or whenever, all devices
are switched off. If you don't use the power discretes
and switch off a device manually though, as Harmony has
to otherwise use power toggle it will switch a device
on that it thinks is already on. Did that make sense?

jlet has explained discrete power settings very well in
other posts. Search for his posts if you need more explanation.

Hope this helps. Rgds, Pfeff