The life of midshipmen can be described as a four-year tryout. The Navy has countless "teams" — cryptologists, submariners, pilots, SEALs — and every Academy student is eventually selected by one of them. Some of the more exclusive teams, available to only the best students, require a top secret security clearance (nuclear submariner is one example). This means another round of tryouts — specifically, a polygraph examination. In that exam, which is used to evaluate an applicant's suitability to handle classified information, midshipmen are asked about past misconduct. If, by answering truthfully, they reveal misconduct that occurred while enrolled at the Academy, their admission can be used against them. In some cases it amounts to a ticket home.