Use of force theory: the law, the situational model and medical risks

The legal framework

Guards may use force only in the same circumstances as any other person. The key Criminal Code sections:

Section	What it says (summary)
s.25(1)	Anyone required or authorized by law to do something in the administration or enforcement of the law (including a lawful citizen's arrest) is justified, if acting on reasonable grounds, in using as much force as is necessary for that purpose
s.25(3)	Force intended or likely to cause death or grievous bodily harm is justified only if the person believes on reasonable grounds it is necessary for self-preservation or to protect someone in their protection from death or grievous bodily harm
s.26	Everyone who is authorized to use force is criminally responsible for any excess
s.27	Force may be used, as much as reasonably necessary, to prevent an offence that would likely cause immediate and serious injury to a person or property
s.34	Self-defence: not an offence if you believe on reasonable grounds that force is being used or threatened against you or another person, you act to defend, and your act is reasonable in the circumstances
s.35	Defence of property: a peaceable possessor (or person acting under their authority) may act reasonably to prevent someone entering, taking or damaging property

Key fact: Being authorized to use force never protects you from responsibility for excessive force (s.26). Use of force must be necessary, reasonable and proportionate, and must stop when the threat stops.

Ontario's Code of Conduct also requires licensees to refrain from unnecessary force, and civil lawsuits for assault or false imprisonment are possible even without a criminal charge.

What makes force "reasonable"? (s.34(2) factors)

Courts consider: the nature of the threat; whether other means were available (retreat, calling police); whether the person is a weapon user; the size, age, gender and physical abilities of those involved; any history between them; and the proportionality of the response.