It is very unlikely that anyone can cover that much material in three days, and even if someone gifted with recall might possibly pass the test it would be of no practical value. When a test like PRINCE2 is administered after a cram session, it displays the test taker's short term memory skills and not their Project Management skills. This misrepresentation ruins the reputation of the person, of the test itself, and the testing process.
I don't know anything about the company making this offer, but I do know a bit about people, teaching, and learning. I would consider this offer as a scam.
In theory, theory and practice are identical. In practice, theory and practice are unrelated.