This is not an idea I would be behind. The idea of reaching the leader-board currently already seems like an impossible and challenging task as I only joined last month and many people obviously have a head start. At least I know currently I have the option of trading for exp or buying a Pokemon with high exp. It is a massive market that would be removed as it is a way many people make their living on this game. I do understand the point that it would help prevent people getting botted exp however I fear a move like this will cause many more people to resort to botting sadly. If someone is at work all day and only has a few hours of game time (or less for some people), the idea of getting on the leader-board would be near impossible. They will not have the time to train up the exp themselves and without being able to buy or trade for what they need to give them that much needed boost, I do fear many people in this situation would bot if they are desperate to get onto the leader-board.