While the likelihood of every single reference being checked might vary depending on the context (a high school paper versus a doctoral dissertation, for example), the consequences of getting caught are significant. They can range from failing grades and retraction of publications to expulsion from school or loss of employment. Many universities use plagiarism detection software that can identify copied text and cross-references your citations with existing databases.
Even if you think you can get away with it, the risk far outweighs the potential reward. The effort involved in creating credible fake references is substantial and the ethical implications are far-reaching. Academic integrity is paramount, and building a reputation of honesty is crucial for long-term success in any field. Focus your energy on conducting thorough research and properly citing your sources.