Generally, unless you purchase the required rights (or are part of a network that has them), you can expect Content ID to find any non-licensed material in your video which, more often than not, will lead to issuing a 3rd party claim, monetizing your video on their behalf, and possibly blocking your video on certain platforms or in certain countries.
Many channels use material that they don't have the rights to, but, as Content ID gets better and better, and channels grow and become more popular/ more likely to be seen by the right people, everyone will eventually be caught.
