With all due respect, I would ask: what's the point? Unless you have millions of subscribers, you will never rank above the TV and movie studios that created the trailer and uploaded it. So, why try to compete with the original video with a shady re-upload of someone else's content that's not yours.
If you were adding commentary or discussing something related to the trailer in a voiceover, then that's another thing entirely. But to just download movie trailers and re-upload them right back to YouTube, what's the point in that? That's a lot of risk for absolutely zero reward. And if you do make any money off the videos, they'll be claimed by the original creator and you won't get the monetization.
If your subscribers want to see particular TV and movie trailers and are looking for you to provide them, then just add the existing original videos to a playlist on your channel. That will create a unique digital ID that YouTube will assign to your channel just as if you'd uploaded a new video, your subs will see the trailers they are seeking, and you have zero liability by sharing their work with your audience.