The Bloomberg administration’s plan to equip all the city’s taxis with GPS units has cabdrivers in a tizzy. A large contingent of cabbies recently protested the plan and has threatened to strike if it goes through. Far from the clever little units that prevent families from getting lost on their summer vacation, these contraptions have no navigational use and only allow others to track cabs remotely. Bloomberg and friends see it as a useful tool in reclaiming lost items. (For those of us boneheads who occasionally fail to memorize their cabs’ medallion number, a GPS can help trace the exact car that was at your pickup location at a certain time.) Cabbies, however, see it as a veiled attempt by the city to nail them for speeding and other traffic infractions. And that’s not to mention the $2,900 to $7,200 it would cost each driver that owns his or her taxi. Whether a coordinated strike will bring City Hall to its knees is anybody’s guess. But while cab drivers are known to be an obstinate bunch, nobody wants to cross the UWS woman who left a new pair of designer jeans in a cab.