Quoted from LesManley:Not after the fact. You can't win and then decide to pay because you did well or decide not to after having an off night.
This is the only weird part for me. I can offer to pay for noncompetitive players so they count for IFPA points, but have to gamble paying for them before actually winning? I fall into the category of decent competitive players but rarely the top finisher at the local bar. A first or second place finish would be decent points for me that I'd want to maximize, but wouldn't want to pay for everyone who didn't unless I'm actually placing.
Honestly I hope my local TD just cuts the prize pool by $1/head or raises the entry fee by $1/head (if those are allowed) just so I don't have to think about it.