Actually, a failure to provide ID by itself is NOT chargeable as any offense in Pennsylvania. You mentioned charging the crime of obstruction. In Pennsylvania, the crime of obstruction is the following:
A person commits a misdemeanor of the second degree if he intentionally obstructs, impairs or perverts the administration of law or other governmental function by force, violence, physical interference or obstacle, breach of official duty, or any other unlawful act, except that this section does not apply to flight by a person charged with crime, refusal to submit to arrest, failure to perform a legal duty other than an official duty, or any other means of avoiding compliance with law without affirmative interference with governmental functions.
18 Pa. Stat. and Cons. Stat. Ann. § 5101 (underlining added).
Refusing to show ID is hardly an act of “force, violence, physical interference or obstacle, breach of official duty.” Nor does it fall under the catch-all of “any other unlawful act” since there is no other statute in Pennsylvania that would make refusing to give identification here a crime. Moreover, the statute says that act the crime of obstruction does not apply “to flight by a person charged with crime, refusal to submit to arrest, failure to perform a legal duty other than an official duty, or any other means of avoiding compliance with law without affirmative interference with governmental functions.” So even where an act might be avoiding compliance with the law, it is not obstruction unless it resulted in affirmative intererfence with governmental functions.
Thus, the Pennsylvania courts have held that even where the suspect gives a false name to police it is not obstruction if doing that did not violate some other Pennsylvania law:
Appellant used neither “physical force or violence” nor “breach of official duty” to obstruct the administration of law. However, the trial court determined that when appellant supplied Trooper Hamer with a false name, he committed an independent “unlawful act” that intentionally obstructed the administration of law. The Crimes Code provides various specific situations when falsity is punishable, but each contains an element not present here.6 In a statute containing many specific sections dealing with falsity to police, we cannot presume the legislature's failure to include this most common scenario to be the result of a desire to penalize it in the “catchall” of section 5101; the more reasonable conclusion is the legislature meant to exclude such a scenario. We find no statute that criminalizes “mere lying” in response to police questioning, and section 5101 does not fill this gap. If giving a false name to the police is to become an offense, it is for our legislature to say so with specificity.
Commonwealth v. Shelly, 703 A.2d 499, 504 (Pa. Super. Ct. 1997).
I have not found any PA cases in which a court upheld a conviction for obstruction merely for failure to give a name, much less to give an ID.
Pennsylvania does not have a separate statute penalizing failure to give ID. If it did, however, the law would only be valid if it required that the person be reasonably suspected of committing criminal activity:
In the absence of any basis for suspecting appellant of misconduct, the balance between the public interest and appellant's right to personal security and privacy tilts in favor of freedom from police interference. The Texas statute under which appellant was stopped and required to identify himself is designed to advance a weighty social objective in large metropolitan centers: prevention of crime. But even assuming that purpose is served to some degree by stopping and demanding identification from an individual without any specific basis for believing he is involved in criminal activity, the guarantees of the Fourth Amendment do not allow it.
Brown v. Texas, 443 U.S. 47, 52, 99 S. Ct. 2637, 2641, 61 L. Ed. 2d 357 (1979).
More recently, the court refined that requirement as follows:
Petitioner argues that the Nevada statute circumvents the probable-cause requirement, in effect allowing an officer to arrest a person for being suspicious. According to petitioner, this creates a risk of arbitrary police conduct that the Fourth Amendment does not permit. Brief for Petitioner 28–33. These are familiar concerns; they were central to the opinion in Papachristou, and also to the decisions limiting the operation of stop and identify statutes in Kolender and Brown. Petitioner's concerns are met by the requirement that a Terry stop must be justified at its inception and “reasonably related in scope to the circumstances which justified” the initial stop. 392 U.S., at 20, 88 S.Ct. 1868. Under these principles, an officer may not arrest a suspect for failure to identify himself if the request for identification is not reasonably related to the circumstances justifying the stop.
Hiibel v. Sixth Judicial Dist. Court of Nevada, Humboldt Cty., 542 U.S. 177, 188, 124 S. Ct. 2451, 2459, 159 L. Ed. 2d 292 (2004).
Note that these decisions only go so far as to approve requirements to give a name. It is not at all clear that a state could require more, especially producing some government issued ID like a driver’s license. I think the Court would have significant reservations about statutes that would have the effect of requiring citizens to carry around ID at all times. I certainly would oppose that kind of requirement. We are not a society that, like the old Soviet Union, should stand for allowing police to come up at any time and demand “papers or the gulag.” Such a requirement would be a least a step in that direction.