I see the idea of that Compact promoted as the way to go around the Electoral College thing. But it doesn’t get rid of it. As per the Constitution, the electors still have to meet and vote.
Keeping that in mind, and also that the electors cannot be compelled to vote for a particular candidate (or, if you prefer, may be but it has never been tested), then how do the states that entered into the Compact make sure that the electors actually select the state’s desired (as per the Compact) candidate and not the candidate that won the majority of the votes in the state, if it comes to that?