A weakness in the current token system allows players to gain a large number of tokens at low level, simply by causing themselves to lose exp after gaining the token, to avoid leveling...
I doubt this is how tokens are intended to be earned...
One simple workaround would be to have an exp bonus attached to the tokens, credited to your exp total when adding the token to your board, and not lost if you die.
Thus "forcing" a player to gain levels along with tokens, to prevent "farming".