What a great idea ! ..... think it should be extended to other zoos.
The orangs could squirt anyone over 12 (being generous) who calls them a big monkey, or anyone of any age who bangs on their glass (in that case, the button would have to be connected to an overhead sprinkler) !!
It reminds me a little of the chimp in the Swedish zoo who collected stones, stashed them neatly in piles all over the enclosure so that he could throw them at the visitors.