This is actually one reason why the OPF was founded. Paizo ran into some legal trouble years ago operating as a for-profit company requesting volunteers in the state of Washington, where such volunteers are supposed to be compensated with wages.
As a non-profit, the OPF doesn't have that issue.
I would like to point out that this player did attempt to join us in a recent con that I had setup, and reached out to me to figure out how to do signups on Warhorn at the time. I stated that I would be happy to help them, and sign them up for any events they were interested in playing. No response was ever received to this, but I think that would be a great starting point if for some reason Warhorn is unable to implement what is needed in time.