Still not sure how leaving it in really makes a difference in the amount of condensation which could form unless you leave the system charged throughout the winter which is an impracticality. Arguably, a partially full system (which is what you get by simply filling the
lines) provides more water vapor to condense without significantly lowering the volume of free space available compared with an essentaily emply system. The engineer in me working over-the-top here...
Even if condensation formed, it would be insufficient to fill the
lines to the point that freezing could damage anything.
Guess I have too much free time.