Regarding professional vs amatur researchers, I think that a technically easier distinction would be of posts that were written as a part of some organisation’s work or independently. (So that professional researchers in EA Orgs would still compete for the prize like anyone else). This makes sense, as they got paid for that work and probably would have done it anyway regardless of the forum prize. This would apply to people working on funded independent projects too.
I think that other methods mentioned in the post would be better suited for leveling the playing field.
Regarding professional vs amatur researchers, I think that a technically easier distinction would be of posts that were written as a part of some organisation’s work or independently. (So that professional researchers in EA Orgs would still compete for the prize like anyone else). This makes sense, as they got paid for that work and probably would have done it anyway regardless of the forum prize. This would apply to people working on funded independent projects too.
I think that other methods mentioned in the post would be better suited for leveling the playing field.