Usually the pump is only disengaged in park if at all. if you coast in park it may be an issue but there are more immediate problems then. coasting in neutral with the engine on is absolutely fine unless you have a freak of a transmission made out of glass.
Coasting in Park... A bad thing -- my car did that for a few feet years ago... Luckily, the park lock is spring loaded in the event of such a mishap (but sure as hell made a lot of noise). My pump was always on (even in park) - but significantly high pressure in neutral or higher
Time is the best teacher. Unfortunately it kills all its students.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"