I did install one on the T100 with the sidecar. I have set it to flash three times and then steady. Simply releasing the brake and applying it again starts the cycle over. The cops here use them on their motorcycles. Like Rocky, on my Tiger, I just modulator brakes as I begin braking. While stopped, I briefly flick the brake lever two or three times when I see a vehicle approaching behind me.
The earlier Bonneville headlights are atrocious. If you get them aimed properly on high beam, low beam does a great job of illuminating your front fender and tire. When you properly adjust the low beam, the high beam is great for spotting fling squirrels and airplanes. On my 03 T100, I installed a sealed beam automotive headlight. It appears that the reflector design is the problem. The newer Bonnies may or may not have that problem.