Everyone seems in favour of the OP, screw that, I disagree!
The thing is, and it's pretty important, is
context is completely missing in 99% of movie trailers. You're shown a rapid sequence of shots, completely out of order, with just the right amount and mix of emotion and captivating dialogue to get your attention.
If you really think a 120 minute movie can be ruined ruined by a 1 minute trailer then you can think again.
People like you, like a lot of folks, don't understand the manipulation and power of editing. I can show shot A and then shot B and provide one conclusion. But if I show them in reverse order you will draw a different conclusion. This is done in trailers for film and television non-stop.
Come back in a few months with concrete examples of completely spoilerish trailers and I'll believe you, I should point out you can't do this exercise with hindsight. You can't do this with a movie you've already seen in full, trailers are built so that they are your first interaction and perception of a movie.
Honestly, I know the feeling, you've seen a trailer, you think you've seen everything. But really you're being manipulated, the movie-makers want you're attention and they'll get that whichever way they can. I've often thought I know what's going to happen, or atleast have some damn good ideas, but never has a trailer completely spoiled a film for me.
The vast majority of details and key story points are left out, and once you're sat down with your popcorn you've forgotten about what you saw in the trailer already.
And having typed all this out, I re-read the OP and realised it was all a bit misdirected...
Watch any recent trailer the the plot will be given away.
So what? I know the plot, great, do I know what happens? Nope.
Do I know how the film unfolds, what occurs in Act I, then Act II, then Act III? Very rarely.
Most trailer's say, hey, here is some of what happens, here's a naked woman which is why you should watch, and here's a memorable line for you take with you. That's it, nothing more.
It's a pencil-sketch outline of the plot and nothing more, I like going into a movie with that pencil-sketch outline, it helps me orientate myself within the film universe and absorb myself quickly.
