Marvel Studios and the Russo Brothers know this, which is why the Endgame spoiler ban was so important to them.
If the Russo Brothers would have had their way, the Avengers: Endgame spoiler ban would have lasted another week.
Marvel Studios and the Russo Brothers went out of their way to make sure nothing substantial about the movie leaked in order to give MCU fans the best possible moviegoing experience they possibly could.
Avengers: Endgame was all Marvel Cinematic Universe fans could think about for a year.