Maybe they should learn to read applications carefully, same as to not give anyone admin unless they actually know what they are doing with that power. Example, I've seen people give each other free admin because they are best friends, yet, that person was abusing everything and banning people for no reason.
You could add a "recommendations" requirement too, including the person's in-game name and bl_id, that way you could try to confirm it with other people if it ever looks suspicious.
Before I admin people I always do a background check, since I've had some bad administration experiences in my server.