A hot topic these days is 'under covers'. In the movie industry this is referred to as 'hiding in plain sight'. A thing to note first is 'under covers' when it's hidden from view, usually by just a select few insiders being privy to it. Sometimes a character will 'hide' out of the limelight and only come out at the end of the movie. 'UNDER wraps' is where a character intentionally slows down a car to hide its true speed or in order to hide its racing skill.
This technique is used heavily in the movies. For example, in Top Gun, Steve McQueen deliberately slows down to avoid being pursued by the terrorists. In Casino Royale, Carlisle is repeatedly slowed down by a limo, again, for the same purpose. In every movie, a character or set of characters does something like this to keep people guessing. This is also done to make it more interesting to the audience.
One well known movie in which this is heavily used is True Grit. The main character, Tom Selleck, is almost buried under a mountain of paperwork. There are stacks upon stacks of receipts and invoices and nothing is close to him. The reason he is able to get into the cabin that he is locked in is because of the 'under cover'. So while other people have to crawl through small openings in the walls, he slides under the mountain of paperwork through sheer luck.
Another well known example is Inglourious Basterds. The SS troops are hidden behind barbed wire inside the camp. Only a handful of eyes are allowed to see them and no one else. Only at the end of the movie do you really see them and they are brandishing weapons. This keeps the enemy camp completely busy while the Nazis attempt to break out.
In the movie Top Gun, Tom Cruise plays a Navy pilot who flies F-14s. He sneaks past the lookout post and starts destroying enemy planes. But because there is no red notice posted, his targets are never told that there is an operation going on. They never know when they are next attacked. Cruise never tells anyone what he is doing either until after the movie ends. In one scene, he hides in the bushes near the runway and snipes one of the bad guys.
These are just a few examples of how the movie industry keeps the plot under wraps. Usually, the only people that know that a movie is going to be good are the studio executives who choose which movies will be made. This is part of the studio method of keeping the movie alive long enough for the box office to come in. Because they don't have to tell anyone what is happening, the quality of the movie will always be higher.