I guess it depends on the AP. Some AP's are pretty linear - start at A, proceed through B, C and D until you get to the end of the AP. The Giants adventure, for example, isn't exactly open world. So, so long as you have a character in hand, you can pretty much proceed through the adventure, and everything is good to go. And, there's nothing wrong with that kind of play. It can be very engaging.
OTOH, if the world is more open, and there's room for side bars and whatnot, or if you're going whole hog sandbox, it's pretty incumbent on the players to actually be engaged with the setting and the campaign.
Proactive vs reactive would be my characterization here. Proactive players take whatever the DM places in front of them and run with it (sometimes into some really, really bizarre directions

). Reactive players more or less passively wait for the DM to roll up the plot wagon and dole out the adventure du jure.
I'm rather fortunate right now to have a group of really, really pro-active players. It's actually hard to keep up to be honest.