okay, i noticed everytime the new trailer (french) is up the authors claimed about the video rights and stuff but isn't normally when tu tape it 'your video', so why do they keep doing that :(

I don't understand lawyers and all their rules.

But you've got to understand that it is footage owned por them, whether someone else records it o not. I can't give tu a good reason for them wanting to borrar it, but obviously it's a marketing strategy. The música companies do it all the time, even if only 5 segundos of their song is used in a video, they still have the rights to get a youtube administrator to take it down.

My only guess as to why they would borrar the trailer is to get tu so hyped up (without any spoiler footage o extra scenes) that tu wanna see NM even más than tu did before (meaning another fan buying tickets, equalling más money). It's very stupid when tu think about it, but obviously it works when tu look at it from a business angle, o else they wouldn't be doing it.
Do I agree with their methods? No. Do I think they're greedy jerks? Yes. Anyways, there's nothing tu can do except watch the vids before someone flags them and they get deleted :/