Keep in mind how easy and fast it is to reach lv 150. You can reach lv 150 legitly faster than the duration of playtime + the 10 day ban. IE took 1h of hack leeching + 10 day ban = 10 days 1h + a warning that next time you will be banned. Vs 2h of player leeching + 0 day ban = 2h. Anyways hack leeching is a tad bit more easy on the player, however with the current rates, can you honestly really complain about that?
Anyways, hack leechers should be banned for atleast 10 days, maybe even more. Depends on how much hacked exp. (/remove exp/, but that is too much work, might as well perm ban and tell them to make a new account.) Hackers should just be perm ip banned.