Senator Pamela Wallin's defence throughout the controversy surrounding her expense claims has been that she wanted to be a different kind of senator when she was appointed to the Upper Chamber in 2009.

"I was determined to be an activist senator, one who saw it as her job to advance causes that are important to Canadians," Wallin said in a statement she read to reporters before attending a Senate committee meeting to hear the results of an audit of her expenses.

Wallin said she believed it was part of her job to say yes to invitations to a lot of events on a wide range of issues.

So she claimed expenses for attending a speech by former British prime minister Tony Blair in Toronto in 2010 on the war in Afghanistan.

Same goes for a meeting with the Nature Conservancy of Canada, about environmental issues in Saskatchewan, or for a flight back to Ottawa in May 2011 to attend a reception at the prime minister's house to celebrate a National Arts Centre program called Prairie Scene.

Deloitte auditors ruled all of these events were personal in nature, not Senate business, just some of the travel claims she is now being ordered to repay.

But Conservative Senator Hugh Segal disagrees.

"She would not have been invited if she wasn't a senator from Saskatchewan, and the notion that she wouldn't be supportive to represent the best of arts in the Prairies when they're coming to Ottawa for a major exposition would be unlike her or any other senator," Segal told CBC News Tuesday.

Segal said that because of Wallin's profile, she did get more invitations than most — and she likely said yes too often.

Check with officials

Liberal Senator David Smith said Wallin does work hard, but he doesn't buy the argument she is a different kind of senator.

"Well, we're all who we are. I've sat on lots of boards, you know I'm still on some boards, but I don't know that makes me different," Smith said.

Smith said that, over the years, if he's ever wondered whether an invitation is for Senate business or personal, he checks with officials before he files an expense claim.

Conservative Senator Gerald Comeau, who chairs the committee that sent the audit to the RCMP, said that's an option for any senator.

"If she had difficulty with it, obviously, she, or if any senator has any difficulty in understanding the distinction between the two, they could come to the administration and seek guidance and seek advice," Comeau told reporters Tuesday.

Liberal Senator James Cowan said he believes most of his colleagues have no problem with the distinction.

The federal auditor general will find out if that's true, when he conducts his own review of senators' expenses, including travel.