For my own part, I'd like to emphasize some of the reasoning behind this (long-standing) position of the government of the Order. Sponsors should not be empowered to create extrinsic ordeals for the Degrees, which phrase in other contexts might be glossed simply as "hazing." Even if such is done with noble intentions and to the educational benefit of the applicants, the sponsorship requirement is not intended to give sponsors the authority of gurus or preceptors! Most importantly, sponsorship itself should be viewed as the responsibility of the sponsor to be acquainted with the candidate, not for the candidate to "prove himself" to the sponsor.
Keep in mind that these degrees are not seals on attainment, but opportunities for attainment.
No one is obliged to sponsor anyone. It's totally okay to say, "I'd be more comfortable sponsoring you if you showed more interest in our basic ritual practices. Would you be willing to demonstrate X for me?" It is most certainly okay to say, "I won't consider sponsoring you until you pay me back the money I loaned you." Likewise, it's fine to say, "I can't sponsor you at this time, and if you want to advance now, you should ask someone else."
It's actually not okay -- even for an individual, rather than a local body -- to say, "Anyone who wants my sponsorship has to do X" when X isn't a USGL requirement for advancement. Of course, we can't, and don't particularly want to, keep people from privately considering certain accomplishments as bellwethers of worthiness. But these shouldn't be noised about as quasi-criteria for advancement, nor to distinguish the "more rigorous" sponsorship of Stan from the "laxer" sponsorship of Ollie.
It's also important to note that administrative officers of a local body tend to be sponsors of "first resort" for newcomers, and their individual approaches to these matters serve as models to the other members for sponsorship.