Unless they do watch it illegaly because their country´s release date is so late and they don´t want to read spoilers wherever they look. They, of course, buy the DVD once released since the quality of those copies usually sucks and they want to support future Bionicle movies and fully enjoy the movie.
Well I somewhat doubt it, most people are too cheap to care of quality over just watching it.
But, you kinda just said what if they do the opposite of what I just said.