There is nothing like a sail at night, especially when the moon is up, and provides just enough light to see it's reflection on the water. I have done it on my cat several times at Lake Powell, in Southern Utah/Northern Arizona.

One of the last times I was out I met up with a Park Ranger who wanted to write me up for not having proper lighting. I had front red/green lights and one light (flashlight) duct taped to the back of the boom for stern lighting. The stern light was not powerful enough to be seen from 2 miles (the law). However, I was able to show that I was visible enough that he could see me in the first place, so I was able to get out of the citation.

My advice:
1. Know the law (State and Federal) better than the Rangers, and have brochures showing proper lighting for sailboats.
2. Make sure you have all the other safety items on board (flotation device to throw, whistle, oar, etc)
3. Know your body of water well.
4. HAVE FUN, THERE IS NOTHING LIKE IT!