So I dug out my fluorescent orange surveyor's tape and tied on a 40 meter piece of it on the landing gear of my UPair One and took flight. It was a windy day so the effect was minimized by the wind, but it was a successful flight.
If you do this, you have to be very careful not to descend too quickly or your props will become entangled in the streamer, at that will lead to a crash. In fact, I ended up crashing from about 20 feet high becoming entangled in the streamer. No damage but that's what you risk. I also feel that there was little to gain from this experiment by flying on such a windy day. Nothing artistic could be done as the streamer hung limp while traveling downwind and strait out flying upwind. I'll have to try it again in Zero wind and see if I can get anything artistic from it.