Note that only for current mavericks a delegation up to 100,000 Staked SPS will be allowed to keep current Maverick status active.

What's the point of this carve out? To me, either allowing delegated SPS makes sense, or it doesn’t… there is no point to a half-measure.

So why would you "grandfather in" anyone that doesn’t want to own enough SPS to qualify?

Carving out a delegation/rental loophole for existing mavs sounds like they can rent, beg or borrow staked Sps whenever they want to look like a mav but don't actually need to stake or otherwise stay committed.