As Ontario's election campaign rolls on, the list of Progressive Conservative candidates who've been conspicuously absent from so-called all-candidates meetings keeps growing.

PC nominees for the June 7 election have skipped meetings in at least 25 ridings across the province, according to confirmed reports compiled by CBC News as of Friday morning. Candidates from other parties have certainly missed some debates as well, but the PC absences are wider in scope.

Some observers have questioned whether, like the federal Tories during the 2015 election, the provincial party has instructed candidates to avoid the scrutiny of all-candidates forums.

Asked about the issue on the campaign trail this week, PC Leader Doug Ford said it was the "first time" he's heard about it, adding, "I don't think they're afraid to answer questions.

"I've never told them not to go to a debate," he continued.

He also pointed to a May 15 event hosted by the Ajax-Pickering Board of Trade that was attended by PC candidate Rod Phillips. The Liberal candidate in the new riding of Ajax, Joe Dickson, was not at the debate.

It should be noted, too, that candidates are often inundated with invitations from various groups to discuss issues at all-candidates meetings. Similarly, a candidate may skip or miss one event, but attend others.

But the growing list of absent candidates at these forums is an "extension of a more general trend that we've seen in Canadian politics for a long time," said Chris Cochrane, associate professor of political science at the University of Toronto.

At both the provincial and federal levels, political parties are increasingly turning to a "leader-centric" model to win votes. Over time, local candidates have become "less and less relevant," Cochrane said.

"To the extent that parties want to run smooth campaigns focused on leaders and focused on the party brand, the last thing they want is candidates who may not be perfectly equipped to go out and say whatever they have to say," he explained.

With the public's focus on the leaders and the various brands of politics they represent, candidates may not see much strategic value in attending all-candidates meetings. Tories running this year could be especially skeptical, Cochrane said, because "it's not entirely clear" what the PC platform really is.

Last November, when Patrick Brown was still at the helm of the party, the PCs released a costed campaign platform called the People's Guarantee. The PCs subsequently scrapped the plan after Brown's abrupt resignation in January. Ford's campaign team has said a new costed platform is coming before election day, but 20 days out from the election, one has yet to materialize.

"Really what they're doing it hitching their fate to the brand of the leader," Cochrane said about candidates who are on the campaign trail without a core platform.

When it comes to ensuring that candidates stay on message, the PCs are far from alone.

"To the degree that they are preoccupied with winning, all the parties have pretty much the same lack of confidence in their members. And I don't think it's individuals, I think it's that they see themselves as having the best chance to win as a united, coherent team," Cochrane said.

Below is a list of ridings where PC candidates have reportedly missed all-candidates meetings. In many of these ridings, however, they have appeared at other community-organized forums or are scheduled to attend events in the coming weeks: