Keep in mind noobs are only noobs for so long (unless you're of the mentality where eveyone with a lower combat level than you is a noob, in which case you're someone elses noob). I'd keep the quests. I'd like to throw out people under 13 (too immature), macroers and scammers. However if I can only choose one, I'd say people under 13. Macroers will only get their own accounts stolen, and scammers will eventually get caught.