well, that was an entertaining thread
Thought I would add another example...
Like gameglaux said (maybe a little poorly), if you don't want the single tap code to execute, you have to add a delay and wait to see if there is going to be a double-tap. After a short delay, if there has not been a double tap, then you can execute the single tap code. The single tap event will always fire, so you have to come up with a method of waiting. The double tap event does fire if there are two quick taps on the sprite.
I took up gameglaux's challenge and make a capx where you single tap to destroy a sprite, or double tap to make it flash. It took 4 events (plus two to spawn a new sprite to try again).