618, 621 (1990). Nor were the officers obliged to abort the stop even if they had noticed the improperly affixed sticker prior to questioning. A driver with a temporary sticker is obliged to display the sticker prominently at all times, and in this case the sticker was not readily visible. Furthermore, after the officers had properly stopped the vehicle to investigate the lack of visible registration plates, the occupants themselves, through their own lack of candor, provided additional bases for further investigation.
D. Probable Cause to Arrest
The most intrusive encounter between a law enforcement officer and a citizen is the full arrest, which requires that an officer have probable cause to believe that a person has committed or is committing a crime. See Dunaway v. New York, 442 U.S. 200, 208 n. 9, 99 S.Ct. 2248, 2254 n. 9, 60 L.Ed.2d 824 (1979) (citing Brinegar v. United States, 338 U.S. 160, 175-76, 69 S.Ct. 1302, 1310-11, 93 L.Ed. 1879 (1949)); United States v. Valencia, 913 F.2d 378, 382 (7th Cir.1990) (“Probable cause involves a practical, common sense determination about whether, given all the circumstances present, it is reasonably probable that a person has committed or is committing an offense.”). Mr. Tipton argues that the officers lacked probable cause to arrest him for obstruction of justice. His first argument is that, because the car bore a temporary sticker, reasonable suspicion for the stop fell away and the stop was therefore improper. We have rejected this argument above. No further discussion is warranted.
Mr. Tipton also asserts that giving false names cannot constitute the basis for an obsti’uetion of justice charge because of the “exculpatory denial doctrine.” See People v. Brooks, 51 Ill.App.3d 800, 9 Ill.Dec. 802, 367 N.E.2d 236 (1977). He argues that, under this doctrine, he could not be prosecuted for obstruction of justice by giving a false name to investigating officers because giving his true name would have constituted an admission of guilt that he had loaned his driving document to Graham. Such an act, he notes, is a misdemeanor under S.H.A. 625 ILCS 5/6-301 (1993).
The government maintains that the fact that Mr. Tipton gave the officers a false name, first in conjunction with one birthdate and then in conjunction with a different false birthdate, in combination with the officers’ suspicions that the car might have been stolen in a high-theft part of town, gave them probable cause to believe that Mr. Tipton had obstructed justice. Indeed, at the time of the arrest, the officers had no confidence that Mr. Tipton had revealed his true name. By offering false identities, Mr. Tipton was effectively preventing apprehension and obstructing the prosecution of himself or Graham. The government also submits that properly identifying oneself to a police officer in an investigatory stop situation cannot be construed as an admission of guilt for purposes of the exculpatory denial doctrine, and that the doctrine applies only when a defendant has been charged with an offense.
We begin our assessment of this contention by analyzing the relationship of the exculpatory denial doctrine to the offense of obstruction of justice under Illinois law. Obstruction of justice occurs when a person knowingly furnishes false information with the intent to prevent the apprehension or obstruct the prosecution of any person. See S.H.A. 720 ILCS 5/31-4 (1993). The contours of the “exculpatory denial doctrine” remain vague and indistinct. The basic definition was set forth in People v. Gerdes, 173 Ill.App.3d 1024, 123 Ill.Dec. 535, 540, 527 N.E.2d 1310, 1315 (1988). There the court stated that the doctrine provides that an individual may not be prosecuted for obstructing justice “for falsely denying to police or investigative authorities (1) that he was involved in a crime, or (2) that some other person was involved in a crime and that crime is inextricably connected with the crime against him.” In Brooks, 9 Ill.Dec. at 804, 367 N.E.2d at 238, the court reversed an obstruction of justice conviction because it determined that, following their arrest for attempted murder, the appellants’ statements denying any knowledge about the incident were merely exculpatory. The grand jury did not indict them for the attempted murder but did indict them for obstruction of justice occasioned by their denials. The Brooks court characterized their denials as efforts to defend against an accusation of a crime: “The answers were made to police at