The purpose of this system would be to encourage RP between lower level characters and pinned characters, while also giving small boosts to both.
A pinned character would have the option to "squire" a character in their clan (with alignment restrictions). This would be an accept/decline thing and would need a place on the score sheet for the pinned character to say "Squire: X" and the low character "Mentor: X".
By being a mentor you would gain 1rp point for every 5th level gained by your squire, double RP points when helping level, and the relationship in general would be great fodder for RP opportunities and RP logs points.
The squire would gain a passive XP boost (maybe 1.25 or 1.33%) until level 50 and a skill/spell learning boost (also 1.25 or 1.33%).
I believe this would help low level characters be taken more seriously while naturally integrating RP potential. The rewards make it desirable for both sides and would help grow the RP aspect of the game.