Just a quick note about banners. Once you get slow with a banner attached, be careful when dropping it as the banner may have a stabilising effect on the plane, ie keeping the tail down and the wings level, which will immediately disappear upon release. A plane (and unfortunately the pilot as well) were written off years ago when they got slow on the pickup and the pilot decided to drop the banner to increase his margins. He (probably, he never got the chance to explain) was already pretty near the stall or in it, and losing the force of the banner pulling the tail down caused the aircraft to immediately enter a spin at low altitude.
This effect has once been demonstrated to some relevant people as far as I know. Airplane in stalled condition but with banner attached -> nose high, wings level descent. Banner release -> immediate nose drop, and violent wing drop to a nearly inverted attitude. Conclusion: if in a stall with banner attached you might be better off leaving the banner attached as it could help you hit right side up, providing you with some protection from the collapsing gear and aircraft structure underneath your rear end.
(Mind: all this is compiled from lengthy discussions with many persons after the accident, not from personal experience.)
I do agree that for a ditching scenario losing the banner would be best because of the reasons mentioned earlier.