Well, there is a potential for a conflict of interest. However, the key is to have clear supervision by the committee. The individual is only one member of the committee, easily outvoted by the majority of the others. Does the individual present all the receipts to the treasurer? Do the rest of the committee view the accounts? Does the treasurer bring any unusual expense to the attention of the committee and periodically report on how the year is progressing relative to the budget? I think this sort of thing can be managed appropriately if there is trust and goodwill on one hand but clarity, openness and supervision on the other hand.