A high % restock fee would make folks think twice about over buying.
As far the the bots, to my knowledge PV doesn't have that issue. They have some curveballs on items and throughout the day they do things with their website that most probly don't notice. These things also alert me a potential drop coming. I've missed some drops but I'd bet combined between me and another buddy we've got close to 100lbs from PV since January, whether it's for us or to buy for friends. Ive helped a few members on here the last couple days get powder they've needed (they know who they are).
Do high demand powders sell fast? Yes.
Do other sites have a bot problem? Yes, some But I don't think PV does.