Yeah, I know a fair few fans of the franchise who still haven't had chance to watch it yet, due to other commitments - kids, holidays, work etc, especially when those factors combine.
I've literally had one chance to see the movie since it came out, due to moving cities, setting up a new house with my wife, important family visits and work - carving out over three hours (not even factoring in travel to get to a cinema) was not easy, despite all my best efforts.
And my problem is, I work in both comic book and entertainment industries, and online. Had I not seen the movie already in that one chance I had, there would have been ZERO chance of me not getting spoiled by now (not even my timeline and Google filters have been able to catch everything).
I know I'm a rare example, given my work circumstances, but regardless of that, I've been a comics reader and Marvel fan for over 34 years. Having some of those big moments even hinted at, let alone flat out shown, would have annoyed me to no end. It's definitely not just the casuals who may not have had chance to see it yet in its 2 weeks of showing.