This is one of the many reasons why you're awesome. I've only just realised you can set a minimum level requirement for players trying to apply to your guild.
This will definitely help filter out the gold digging low levels that want to join because of 3X Guild Money bonus.
(Fellow Guild Leaders, you can set the level requirement in the guild description edit. You all probably know this by now but I'm a bit slow and I only just figured it out today.)