n. — especially Ontario & Western Canada, informal, usually Politics
an event where candidates or elected officials face intense questioning.
Type: 1. Origin — The term bear-pit session connects metaphorically to the perceived ruthlessness of the questioning, in which someone powerful is attacked,like a bear by dogs. The term is exclusive to Canada, as demonstrated in Chart 1. Although newspaper attestations come from all regions of Canada, the term is most prevalent in Ontario and the Canadian West (see Chart 2).
See also Gage-5, s.v. "bear-pit session" and COD-2, s.v. "bear-pit session", which are marked as "Cdn."; not in ITP Nelson.
Images:

Chart 1: Internet Domain Search, 5 Nov. 2013 
Chart 2: Regional Domain Search, 18 Nov. 2013