While we're talking about ways to limit output of message delays (etc.), check out also the [debounce] abstraction in extended.
Alexandre's attached idiom is quite common in other areas, too, like protecting a [readsf~] from all input until it has finished playing, or halting all input to a synth abstraction while it is generating an event. One strategy I like even more is finding a way to route all the incoming information intended for the object in question back out for further processing (perhaps another delay or readsf~ or synth abstraction is open and can accept the event).