I know someone who's either shot one or two of the arrows. Nothing fun to f around with.
One or two isn't bad, I shot 7 Gold Musketeer Bolt (Bastok's PPA equivalent) before giving up.
Last 4-5 I had them for a while tho, safest way to use those is to have 3 macros for it:
A) A recast one to know if Unlimited Shot is up (/recast) (I put all abilities in that macro, barrage, sharpshot, berserk, etc.)
B) A SEPERATE macro for Unlimited Shot, donT put it in your WS macro. That way you can see if the animation happens or not and avoid lag while using a WS macro.
C) A different macro for WS with PPA, along with a regular arrow WS macro. Put the PPA one AFTER the regular one, worst case scenario is you use the regular macro with Unlimited Shot, reducing DMG but you keep your PPA.
Also, don't swap ammo back to regular in your PPA-WS macro. Instead, use /equip Ammo "Demon Arrow" in your regular RA macro. That way you automatically reload when you're out of ammo and you always switch ammo back after a WS.
Still, there's always a chance of shooting the PPA if you're out of Demon Arrow, on your next regular attack. Best way to keep your PPA is to stay cool, don't try to force a WS in before a mob dies, that's usually when you go to fast and shoot it without U.S.