<<The employment application is origin of the data to determine whether the company is diverse enough to avoid
discrimination law suits. By law, this portion of the application must be voluntary but at the same time, this is the
only data they are allowed to use when legal questions about diversity come up.>>

I hope that you are not saying that the only people that opt not to fill out this section are "diverse" employees. If so, what basis do you have to assume that? From my personal experience, HR has filled this section in for me, using the erroneus assumption of my physical appearance. After raising a stink, they have erased the marks and apologized profusely for making such assumptions. This has happened at 4 different places of employment. Who's to say your company doesn't employ such policies too? No offense, but you may be raising this point irrelevently. Perhaps their are other motivations behind your company's bonus distribution...?

-Angela