But the problems appeared to stem more from misinformation than malicious voter suppression, and officials - both supporters and opponents of the Voter ID law - said those instances did not undermine the validity of the election.
The irregularities appeared to vary by location, with poll workers in Democratic-leaning Philadelphia more likely to skip even asking for ID, and those in Republican-leaning suburban precincts more likely to aggressively push for voters to show an ID.
Several voters from Philadelphia and Montgomery and Delaware Counties told election watchdog agencies that they were ordered to use provisional ballots after refusing to show an ID. But those reports could not be confirmed Tuesday night.
More frequently, voters came to their precincts confused about the rules, and some poll workers and polling signs spread inaccurate information. "There's a lot of honest misunderstanding, and maybe some not-so-honest," said Zack Stalberg, CEO of election watchdog Committee of Seventy.
Several polling places in Montgomery County had posted signs that said voters were required to show a photo ID at the polls.
Montgomery County Commissioner Leslie Richards said the signs were printed by the state and included in a packet distributed to polling places. Similar signs were reportedly posted in some Delaware County polling places, and sheriff's deputies were sent out to make sure they were taken down.
Richards, a Democrat in a county that had been under Republican control for 140 years, said that the signs were outdated and that each polling place had been instructed to take them down.
Similar signs were spotted in Butler and Crawford Counties.
A State Department spokesman said the signs were printed before a judge halted enforcement of the state's controversial voter ID law, and county officials were instructed not to use them.
Republicans passed the Voter ID law in the spring over Democratic objections. The law's strict requirements for voters to produce photo identification were challenged in court by the NAACP and others, and Commonwealth Court Judge Robert E. Simpson Jr. ruled on Oct. 4 that the law could not be enforced for this election without disenfranchising voters.
Simpson delayed its implementation until after the presidential election.
But he did not order the state to halt its efforts to inform voters about the law, so fliers with incorrect information continued to surface leading up to Election Day.
"I think we will never be able to measure - and this is the most important thing, really - how many people stayed home because of confusion over voter ID," said Philadelphia City Commissioner Stephanie Singer, a Democrat who oversees the city's Board of Election with two other commissioners.
In the hierarchy of voting problems, Singer said, disenfranchisement is "absolutely No. 1." Consequently, she was less concerned about reports of first-timers' IDs not being checked, but said it was important that voters have confidence in elections.
Val DiGiorgio, chairman of the Chester County Republican Party, indicated that Tuesday's voter ID irregularities weren't particularly alarming. But he said he witnessed several instances in which would-be voters were "pretending to be someone they weren't," and left after being challenged by poll-watchers.
He didn't expect those cases to be investigated and said they were "just more evidence that we need a voter ID law and we need to purge inactive voters from the rolls."
The confusion surrounding voter ID was arguably lower than expected, but it extended beyond the polls.
At least a hundred people waited inside the PennDot Center on Arch Street late Tuesday, many of them there to obtain photo IDs they thought they needed to vote.
Olivia Rodriguez, a 29-year-old nurse from South Philadelphia, had waited more than an hour at PennDot specifically because she thought she needed to present election officials with an ID in order to vote.
H Brawley, 53, of South Philadelphia, was at PennDot to renew his driver's license, which expired in 2006. An Obama supporter, Brawley said he thought he needed the new ID to vote.
Other voters were well-informed about their rights, and refused to show an ID on principle.
At the East Coventry polling place in Chester County, at least 50 people by 10:30 a.m. had refused to show their IDs, said Constance Megay, the judge of elections. She fumbled for words as she tried to describe their demeanor. "Very stern," she decided.
Bernadette Brungess, a 69-year-old retired die-cutter, said she thought requiring IDs was "a good idea, really, so you don't have people in here who were here three hours ago." She said she feared they would come in using someone else's name and be able to forge their signature on the voting register.
Mark Cinkowski, 38, a financial services worker, refused to comply. "I told them I wasn't going to show mine," he said. "It's a voter oppression tool."
But when he got to the sign-in table, workers told him that because it was his first time voting in this location, he was required to show identification. He did, but he wondered, "is this legal?"
Contact Jessica Parks at 610-313-8117 or firstname.lastname@example.org.
Inquirer staff writers Aubrey Whelan, Andrew Seidman and Sandy Bauers contributed to this article.