Yeah, fans do it too, anything that will carry heat away. Brakes stop airplanes by converting kinetic energy to heat. Must remove that excess heat or they do not have the stopping power for a rejected takeoff. Water works better but it is really not done all that often. The fire department might have done that to keep the fuse plugs from letting go. Kind of risky even to approach an overheated wheel.
it is probably more important not to brake too hard or too early, but to let it roll to the far end. That way you don't get the buildup in the first place.
Leaving the parking brake set with high brake temps is a bad idea. First, they don't cool as quickly when they are all bound together like that and second, if they are hot enough, they can "weld" the rotors to the pucks.
Happiness is not seeing another trite Ste. Maarten photo all week long.