The guidelines permit distributing tickets for six reasons, including: to serve as a thank-you to community leaders; as goodwill offerings for economic development; to reward city officials and employees and their families for good work; and to provide the mayor, friends and family with "reasonable opportunity" to attend the events to support the venue.

The mayor's office has said that previous mayors also attended arena events at no charge under the terms of the city's agreement with arena operators. Officials said the mayor's office often donates tickets to events, including Baltimore Blast soccer games and the circus, to children and community groups. O'Doherty has said there is "zero evidence that any part of this is new or out of the ordinary."

The mayor has used the tickets to attend high-profile concerts with friends and family. For instance, Rawlings-Blake accepted four tickets in May to see 1980s boy band New Edition. Top aide Kimberly Washington received four tickets, and Teminka Rawlings, the mayor's sister-in-law, received two. Other city officials and state Sen. Nathaniel McFadden also attended the show as guests of the mayor, according to city records.

In another example, Rawlings-Blake's husband, Kent Blake, obtained six tickets from City Hall to see pop star Rihanna in concert in June of 2011. Teminka Rawlings received two tickets, as did then-Mayor Adrian Fenty of the District of Columbia. At least nine other tickets went to the mayor's top aides.

In one instance — a Jay-Z concert — the mayor's office received more tickets than the 35 permitted by the contract, records show.

Rawlings-Blake's use of free tickets became the subject of public debate after she took back Ravens tickets this year for the mayor's skybox at M&T Bank Stadium from City Council President Bernard C. "Jack" Young. He had criticized her support of the Baltimore Grand Prix.

In its opinion Wednesday, the ethics board acknowledged that past administrations have accepted and distributed free tickets from 1st Mariner. That long-standing practice convinced the board that "any Ethics violations that may have occurred were inadvertent rather than intentional," board members wrote.

Rawlings-Blake's law office has said it can't find the current contract that it has argued allows her to accept free 1st Mariner Arena tickets, but does have an older, 1988 version of the agreement with the arena that permits the behavior. The 1988 agreement permitted 1st Mariner to award 35 free tickets to the mayor per event, as available.

In a letter submitted to the ethics board, 1st Mariner General Manager Frank Remesch said Rawlings-Blake had used fewer free tickets than previous administrations.

"It has always been the practice to provide the mayor's office with a small portion of complimentary tickets when available," Remesch wrote. "Due to the ever-changing climate, the current administration has received fewer complimentary tickets than the prior administrations."

The 1988 agreement, signed during former Mayor Kurt L. Schmoke's administration, provided for other free ticket provisions, including requiring the management to honor 30 "lifetime gold passes" and 33 transferable passes to the arena. The contract said the mayor would select recipients if the passes were transferred or expired.

O'Doherty said a new contract for operation of 1st Mariner Arena is expected to be approved next week. He said it will include "essentially the same ticket provision," referring to the 35 free passes.

Proposed reforms

•A prohibition against accepting more free tickets than permitted by the contract with 1st Mariner.

•A list of legitimate city purposes for distributing the tickets.

•A formal tracking system for recording who receive the tickets, including the recipient's full name and title and which legitimate city purpose is served through the ticket distribution.