As I understand it, their decision was based on the RC planes being the heaviest things being flown on their property, combined with the engines and the possible liability either from the flyer losing control, or from radio interference, at the college or our field. The college campus is quite large, but is surrounded by a heavily traveled state route on the west side, and has considerable residential and business property and development all around, as well as their own community oriented CoC developments. The FF group rarely flys anything weighing more than 2 ounces, and the CL flyers not only have the direct connection with the plane, but one of the security people actually got to see what happens usually to a CL plane when one of the lines breaks. Usually, they don't travel far. Also, the CL planes were't observed flying over campus structures or parked cars, any time of day, including when classes were in session, like some of the RC flyers had done. Kites are generally regarded as harmless, unless somebody gets a string cut, and the model rocketry people seem to be able to keep their models on a relatively small part of the field, and fly well away from campus structures and don't fly near any of the youth soccer set-ups or the tennis courts.
Also, several of the RC flyers who used the college, but didn't try to contact our club, presented the image of "I'm going to fly what I want, where I want, and any way I want." according to the security head. Not smart people!
We maintained good relations with the college, even getting invited to put on demos, flying and static, during their annual community days.