11:47 ET Mike Tarsala's TechWatch Alert -- ZBRA (ZBRA) 50.14 -5.89: Zebra Technologies is sliding as a rumor spreads on trading desks that the co might lose an RFID contract with Wal-Mart. We've left a message at ZBRA and haven't heard back yet. If that's the case, the selloff could be overdone. We know Wal-Mart (WMT) is not a customer that makes up 10% or more of revenue,