A wireless fencing system comprises a tetherless leash, a programming fixture, and, optionally, a terminal. The number of separate grating structures thereby can be reduced to two or even one, compared to three in the prior art. The system and method require that the calculation of the amount owed to the third party occur at a WAN node that is different than and at a different locale than that of the merchant. The level of the filling in the container is determined using the weighted sampling values.