Major League Baseball postseason games will be available live online in U.S. for the first time, but there’s a catch and it’s, well… major. Access will be limited to 23 participating airports as a special four-hour pass to the “Airport Edition” of MLB.tv. Moreover, the $4 four-hour pass will only provide access to the division series and American League Championship Series games. TBS, a partner on the deal, doesn’t have national broadcast rights for the National League series. MLB.tv subscribers will, however, gain access any postseason game from the site’s on-demand archives. One last catch: the offer’s only available to Boingo customers who are logged into their Wi-Fi subscription at one of the 23 airports. So baseball fans who might have their own internet access will still have to purchase a one-time access to Boingo’s Wi-Fi network, which has more than 100,000 hotspots worldwide at airports, hotels, cafés and metropolitan areas.