Our club doesn't use the 10ga cannon anymore either- they used to use it for the "gun" on Race Committee- but too many people blew holes in gelcoat or canvas with the blanks to make it seem safe. We now use a sawed off shotgun & blanks, which would be a little safer (though not much- couple of people ended up paying for repairs when the blank blew a hole in somebody's sail).
I give the occaisional nut on the powerboat a salute- but hand gestures are free. Who else are you saluting?
Chris