I know you aren't asking about decorations during Christmas, but I wanted to pass along this story as a "warning".
We did decorate with some lights at VWL during our Christmas stay a few years ago. In our handout at check-in they specifically indicated that
illuminated decorations were not allowed on the balconies and may be removed if displayed.
I asked a couple of CM's about that and they said it protected Disney (surprise, surprise) in case anyone complained about the lights they had the right to pull them down without permission. They told me to go ahead and decorate if we wanted to, but if we came back at some point and the lights were gone it meant that someone complained about them.
I guess nobody complained as we had them up for the entire week.