THE FOURTH AMENDMENT REQUIREMENTS OF REASONABLE SEARCHES AND SEIZURES BASED ON PROBABLE CAUSE ARE 'TERMS OF LIMITATION' PLACNG A RESTRAINT ON GOVERNMENTAL LAW ENFORCEMENT ACTIVITIES. THE SUPREME COURT HAS UPHELD WARRANTLESS SEARCHES WHEN BASED ON ONE OF THE FOLLOWING CIRCUMSTANCES: CONSENT; HOT PURSUIT; AN EMERGENCY; A BORDER SEARCH; A 'STOP AND FRISK'; MISPLACED TRUST; ABANDONED PROPERTY; THE ACTIONS OF A PRIVATE CITIZEN NOT ACTING IN CONCERT WITH LAW ENFORCEMENT AGENTS; CERTAIN ADMINISTRATIVE SEARCHES; AND EVIDENCE FOUND IN PLAIN VIEW. THE COURT HAS CREATED AT LEAST THREE CLASSES OF WARRANTLESS SEARCHES NOT REQUIRING PROBABLE CAUSE PRIOR TO SEARCH AND SEIZURE: BORDER SEARCHES; 'STOP AND FRISK' OF SOMEONE UNDER 'REASONABLE SUSPICION'; AND CERTAIN ADMINISTRATIVE SEARCHES. ALTHOUGH THE RIGHT OF A POLICE OFFICER TO CONDUCT A WARRANTLESS SEARCH OF AN ARRESTEE HAS LONG BEEN RECOGNIZED BY THE SUPREME COURT, THE SCOPE AND TIMELINESS OF THAT INTRUSION HAVE BEEN MATTERS OF DISAGREEMENT WITHIN THE BURGER COURT. IN THE MAJOR OPINIONS OF THE BURGER COURT FROM 1972 THROUGH 1976 INVOLVING SEARCHES INCIDENT TO CUSTODIAL ARREST, THE COURT HAS DEMONSTRATED A WILLINGNESS TO NARROW THE SCOPE OF FOURTH AMENDMENT PROTECTIONS FOR THE ACCUSED THAT HAD BEEN EXPANDED BY THE WARREN COURT. ALTHOUGH NO SINGLE DECISION SPECIFICALLY OVERRULES ANY EARLIER PRONOUNCEMENTS OF THE COURT, THE DECISIONS TAKEN TOGETHER SUGGEST A DEPARTURE FROM THE EXCLUSIONARY RULE RESTRICTING WARRANTLESS SEARCHES TO WELL-DEFINED EXCEPTIONS.