Let cabal members see online pledges via "who pledge". This would be disabled for "secretive" cabals (e.g. Scion). For Empire it would only shows pledges whose class would put them in the caller's sect, unless you're on the Council in which case you see them all. For Outlander maybe it only shows pledges of the caller's same alignment.

Beef up the output of "who pledge" for cabal leaders. Maybe include "RL Days since Pledged", "Game Hours Since Pledged", etc. Downside: that's sort of OOC. But it seems like it might be useful to leaders who're trying to decide who should get their time. It doesn't immediately strike me as vulnerable to abuse.

Bonus idea: Let cabal leaders configure hard-coded "requirements" for someone to pledge their cabal. Minimum level, minimum number of "cabal relevant" pkills, "must be empowered", etc. This might be useful for ratcheting up the difficulty of pledging when a cabal is "full".