Although you can expect to experience a heightened security presence inside Metrorail stations this weekend, the system is not a target of the “specific, credible” threat which federal officials briefed local leaders about last night.

In what we’re pretty sure is the biggest single rollout of WMATA’s random bag sweeping policy, we’re hearing that the transit agency is currently performing bag checks at three — count ’em three! — stations. Security personnel at Archives-Navy Memorial-Penn Quarter, Franconia-Springfield and Huntington are randomly checking parcels during the evening rush hour, so if you’re heading south on the Green, Yellow or Blue Line, take note and be prepared to be pulled aside if…

UPDATE: Well, that was fast — a couple of DCist tipsters let us know that a gauntlet of greeters at the store’s main exit are indeed checking receipts today — and that refusing search is going to be tougher than simply walking away. One Safeway customer tells us that “calmly refusing doesn’t appear to be an option,” given greeters’ “body language” and “them nearly blocking [the] exit.” However, based on our tipsters, receipt checkers were apparently only stationed at the main exit and not the secondary one leading to the parking garage.