Some moviegoers point out, occasionally, that they've seen that shot or that other shot in other movies. That sure is possible. Film studios, much like any creator out there, tend to borrow some elements they already created for other projects (especially in our digital age where recycling and reusing is easier - and cheaper - than creating).
Sometimes, it's shots 'traded' between two friend companies. Some other times it's purchased between studios. When it's not litterally stock footage, of course.
So there's no scandal here when you see the same stuff in different movies. For instance if Michael Bay's studio paid two hundred thousand dollars for a certain shot, why not re-use it in another movie, and spend five thousand in tweaking it to match the requirements of a new project...
Do they think no one will notice? Of course not. At best, it will cause people to discuss their films, and re-watch them to spot the scenes. Free advertising!