Maybe the T should change the inbound and outbound track signs at those stations to show track numbers, or letters, or call one side "Charlie" and the other "of the MTA", or anything that would be less strange-sounding than 'board the following inbound trains on the outbound platform and/or vice versa". This practice is (a) old and (b) consistent enough that I remember metal signs attached to the fences 25 years ago that said "board trains x, y, and z on the outbound platform," or something like that. The service alert that started this thread is clearly not about particular trains, but simply announcing what happens every day as scheduled. Sure the tracks are signaled for any train to show up on any track, but in practice it's planned and predictable and no one really needs to wait and then race across, right? If inbound and outbound were not painted up prominently and used to identify the platforms, many fewer people would be confused.
While it is true for operational possibilities, and also good safety advice, "expect your train on either track" is not a good strategy for getting passengers on board unless there is a center island platform. It's also not what the T or any other system does: they either schedule which platform will be used and post the schedule, or they announce the track to passengers in good time. The issue here, which is worth someone or everyone complaining to the T about, is that they have been using confusing signs and terminology to get a simple message about a sensible operating practice across for decades, and it still confuses people.