What are the criteria for issuance of an OK to Board?

In this question on the UAE's "OK to Board" approval requirements, Henning Makholm asked in a comment, "...why they don't say anything about under which conditions the local offices will issue their approval ... do you just pay a fee? do they check something else? your credit report? do they flip a coin?".

Other than possessing a valid passport with acceptable UAE visa, what are the requirements for the issuance of an OK to Board approval for boarding an aircraft to the UAE? Is this something that essentially anyone can get if they already have a UAE visa and pay the appropriate fee, or are there more onerous requirements (beyond the basic requirements for a UAE visa) such as deeper background checks, additional sponsorship requirements, a literacy test, etc.?

I did find this page from Emirates airlines, but it does not explain what criteria are actually used - that is, whether issuance of the approval depends solely on entering the "correct" information into the form or whether or not there are additional checks or approvals that go on "behind the scenes" that can result in a denial, e.g. "The biographical data you gave us checks out, your passport looks ok, and you have an appropriate and valid UAE visa, but we looked up your high school grades and they are not good enough for the issuance of an OK to Board. You may reapply after getting further education, see the attached Appendix E for current standard literacy, science, math, language, and social studies benchmarks."