I do not believe you. User prohibited operations are absolutely infuriating. Sometimes you can only skip with the Skip button, sometimes only with Top Menu, sometimes only with Play, sometimes only with FF...you never know until you try them all.
Here's the kicker. Sometimes I want to go BACKWARD to see something I missed in a preview, but THAT'S ALSO A PROHIBITED OPERATION! I've even seen Pause as a prohibited operation! Heads need to roll (figuratively) at these DVD/BD production companies.
Now this is even more infuriating...I've encountered some movies that have absolutely no way to skip the previews. I believe one example was a rental version of The Blind Side on Blu-Ray. On top of that, the previews were lower-than-standard-def and non-anamorphic (black borders on all sides). For some reason, I was forced to restart the disc over and over. Since experiencing that, now I'll want to kill myself if I ever see another trailer for a movie with Steve Irwin's kid in it. On top of that, the amount of forced trailers was far beyond reasonable. Then there was no option for subtitles. There were other examples of movies with absolutely no way to skip previews, but I don't remember which movies they were.
Every format is fucked.