Good way to get either shot or peppersprayed.
On a dark street, pulling out a gun-shaped object of any sort, especially when you can't see the color (sodium streetlights?) is just asking to get shot, especially by a cop.
Remember, Lazer Tag died out back in the 80's after a kid playing it outside around a school after dark was shot and killed by a jumpy cop.
Plus, how do people know what's in a watergun these days? It could be anything from an irritant to gasoline, people have made super soakers into flamethrowers. While it will break down the seals quickly, a Super Soaker will fire naptha, acetone, tolulene, etc. Even Drano. Or if someone is really sadistic, PCP can be made into a liquid suspension, and can affect someone very badly just through skin contact. They'd think it was just water 'till they suddenly went on a bad trip.
Kid with supersoaker = kid playing. Adult with supersoaker = pressurized liquid projection device and possible threat.
If you want to play at shooting people with gun-shaped objects, go to a paintball place or one of the arena-style laser tag venues. Keep it off the street...that's just asking for it.