I've landed ultralights at our model field quite a few times. I never overdid it and actually treated the models as if they had the right of way. That way I was responsible for my own safety AND respected the airspace of the model field. It was a small club (50 members) with very few active fliers. If some one was flying I would loiter behind the flightline till everyone was down and usually they would wave me in. Big fun back in the day