With the PSI behind those hoses?! A gentle setting?! If you stand closer than 30 feet to a hose (which I doubt very much any human being will remain standing at least in the US with a US standard hose) it will not only knock you down very hard but if you're hit at a range closer than 30 feet the water pressure will perforate your skin and cause your skin to seperate from muscle and inflate with water and cause a form of leprosy.... Random fact from the Civil Rights Movement.

Alot of bird clubs have fly days indoors for people who want to do that.

It's highly unlikely that a 4 month old who can barely fly to the sofa is going to get stranded up on ceiling beams of a gym.