I'm going to play devils advocate here.
I have given this some thought. I have enough trouble keeping traffic flowing by my display as it is. If more people got out of their cars to participate in an interactive display I'd end up with a lot of very upset neighbors. I have no place for people to park much less there is no sidewalks in this community. I know this is probably the same for the general display population. Back in Texas I remember a display that offered a walk by option where you had to park blocks away and deal with dodging traffic to walk by. It could create some liabilities for visitor safety.
While it would be cool to have this technology in our displays but IMHO it is not generally practical.
Light Show Pro has built in support for Wii where you can use a Wii to control a light show. I am not aware of very many people using this interface, at least there has been very support questions ever posted relating to using the interface.
It could quickly become a lot of trouble monitoring the use of the interactive interface, keeping people out of the display and tracking any equipment you might have to provide such as the wands or Wii controls.
IMHO This type of technology is best suited for a commercial display where space and traffic is not a problem.
I particularly am cautious about the personal liability aspect of providing something that could present hazardous (traffic moving by) to a participant.
Just a few things to think about.