How do you distinguish

(A) two random developers that met each other at several conferences over the years, have contributed to a few same projects and really like the efforts the other one is putting into their OSS project

(B) two random developers that met each other at several conferences over the years, have contributed to a few same projects and want to fraud GitHub for the donation match

I think this could be a real practical problem for GitHub. And lawyering up against developers supporting the campaign potentially counteracts the marketing benefit of it.