In Ontario, such responsibilities lie under the Occupiers’ Liability Act, says the principal of Yegendorf & Associates.
“If you are in control of a premises, you have an obligation under that Act to ensure people who come on your premises are reasonably safe,” Yegendorf says in an interview with Ottawa’s CTV News at Noon host Michael O’Bryne.
In the winter, that means salting your walkways and taking other measures to protect visitors from injury while on your property, he says. In the summer months, risks only increase when social gatherings involve young people who may be consuming alcohol.
“At this time of year there’s a lot of graduation parties, there’s young people going to cottages around lakes and there’s oftentimes alcohol served in those situations,” Yegendorf says. “Unfortunately young people and alcohol, often doesn’t end well. So you have to be careful in those situations.”
Social host responsibility involves determining whether the person who throws the party or owns the property is liable if someone is hurt, either at the event or, for example, if an accident happens after someone leaves, Yegendorf says.
The law is evolving related to liability for people who have left a social gathering after the Supreme Court of Canada ruled in Childs v. Desormeaux,  1 SCR 643, 2006 SCC 18 (CanLII) that the host was not ultimately responsible.
“But it did leave open the possibility of liability in other situations, particularly, it gave an example when there is a supervisory role played by hosts,” he says. “In other words if you have teenagers attending your home and they’re consuming alcohol, you may be found to have a supervisory role, and if one of those teenagers leaves, and gets in a car accident, you could find yourself being a defendant in a lawsuit.”
Yegendorf’s advice is for adults to take proactive steps to take control over any parties, especially those involving young people and alcohol.
“If you’re going to have a party with kids, bear in mind as G1 and G2 drivers, no alcohol is allowed in their bloodstreams whatsoever when they drive,” he says. “Make sure there’s taxis, encourage sleepovers. Maintain control of the party, if there is a party. Don’t turn a blind eye.”