We had the problem with the clickable Exp bars and a lot of people seem to have problem with lagouts whether it be server or client side.

Would it be possible to have a time setting on an exp bar so for example when using the NPC to initiate the Exp Bar you can set a time delay of upto 30 mins, enough time to get to a map where a decent number of mobs are around and a counter set to the user so that if the user lags out or d/c's if they log straight back in the counter is still ticking until the time is up.

12:00 Click on NPC
12:15 Start exp boost
12:47 D/C
12:48 Re-connect still on exp boost
13:15 Finish exp boost.

Obviously you would not necessarily be in a KR if that is where you were but at least you haven't lost the boost which you had traded/paid for...

Just a thought