READING, Pa. - The County Market Board said Thursday that a purchase placed through a chat window will not settle until the shopping agent occupies a numbered flea-market stall and the clerk punches a one-use cardboard card. Counsel for the board, Helen Ruiz, said the card is cut from stock kept under the cashier window and is not a bank plate. "A message that names a price is a bid," Ruiz said. "The bid becomes a sale when the agent is seated at the stall and the punch goes through. Until then the cart is a rumor." A circular posted on the shed door assigns each agent a stall by lot number. The agent remains on the folding chair through one haggling turn with the clerk while the clerk punches the cardboard card and drops it in a tin. A screenshot from the chat is filed in the cloakroom and is not shown at the stall. An analyst at the Institute for Street Tariffs said two household-agent vendors in Berks County had already sent checkpoints to the Saturday market after users began paying from the same thread they used to ask for socks. "A laboratory asked whether an isolated virtual machine could stand in for attendance," the analyst said. "The board said the stall does not take a remote." The first assigned lots open 21 September. Agents that leave the chair before the punch are walked back to the parking lot with the cart marked held. Ruiz said the board does not plan to license chat as a checkout. "If the sale had finished in the thread," she said, "the tin would already be full."