MOE 365 has been holding multi-program events for the past few years. The best example is our First State FIRST LEGO League tournament in January. This event houses JFLL, FLL, and FTC official events. While sound is generally an issue, these three programs have done very well together in this venue (Bob Carpenter Center at the University of Delaware). The beauty of these programs together is that JFLLers can actually see FLL and FLLers can see FTC. So can their parents, who have much to say regarding what programs their children are involved in and whether or not they themselves volunteer.
We had an FLL student, who was watching the FTC competition last year, say to his parents. "I'm not leaving until I get a Vex Robotics kit." Fortunately, he did not stick to his word, because we were not selling these kits and he had to leave at some point.
Regarding FTC and FRC, we have held an FTC scrimmage at the same venue (Salem Community College) as our Duel on the Delaware off-season event the past three years. While not an official FTC or FRC event, the activity is separated in space and each has a separate sound system. It was great to see the cross-traffic between these two activities.
In general, I believe the potential is great for multi-program events. However, there are a number of factors which come into play to determine if this is the best course of action. These factors include - venue, sound, # volunteers, # teams, organization, etc.
Also, it is very important that the organizing groups for each event work well together. If the organizers see these events as competing, more than likely they will be set up that way. It takes a village to put on a multi-program FIRST event!