Public comment was scarce this week when the Philadelphia Board of Ethics held a hearing on proposed regulations to govern independent expenditures in city elections.

The rules are aimed at preventing candidates from evading contribution limits in city campaigns by coordinating with outside groups with plenty of money to spend.

In past decades, mayoral candidates in Philadelphia regularly got contributions of $100,000 or more.

Now candidates can only accept contributions within specified limits -- $2,900 per year from individuals, and $11,500 from businesses or political committees.

But there's nothing to keep independent groups from taking big contributions and spending whatever they want to help a chosen candidate.

The ethics board wants to make sure candidates don't set up committees of supporters that pretend to be independent or coordinate with independent groups. So the board has drafted regulations defining independent expenditures.

Adam Bonin, an attorney who advises candidates, says it's good to have rules. He said most of those who will ultimately be affected by the regulations are paying little attention to the process now.

Bonin said he's glad the board is trying to give guidance, but said he's concerned an ethics board trying to sniff out coordination may engage in witch hunts, questioning lawyers and consultants in Philadelphia who have multiple clients.

"We all talk to each other all the time. Many of us represent overlapping interests," Bonin said. "I'm concerned about a zealous ethics staff chasing down rabbit holes when there is no rabbit."

The board made a few changes to the proposed regulation at Thursday's hearing. One says the fact that a candidate and an independent committee share an attorney or consultant does not by itself mean they're engaged in illegal coordination.

The regulations could be approved and in place by early March, in time for a contested city controller primary this spring.