Personally I prefer a balanced approach that includes the concept of reasonableness over extreme, inflexible “zero tolerance”. Here is the present state of the law defined by our Supreme Court in 2004. “Section 43, properly construed, is not unduly vague or overbroad; it sets real boundaries and delineates a risk zone for criminal sanction and avoids discretionary law enforcement. The force must have been intended to be for educative or corrective purposes, relating to restraining, controlling or expressing disapproval of the actual behaviour of a child capable of benefiting from the correction. Section 43 does not extend to an application of force that results in harm or the prospect of harm. It provides parents and teachers with the ability to carry out the reasonable education of the child without the threat of sanction by the criminal law. Without s. 43, Canada’s broad assault law would criminalize force falling far short of what we think of as corporal punishment. Generally, s. 43 exempts from criminal sanction only minor corrective force of a transitory and trifling nature. On the basis of current expert consensus, it does not apply to corporal punishment of children under two or teenagers. Degrading, inhuman or harmful conduct is not protected. Discipline by the use of objects or blows or slaps to the head is unreasonable. Teachers may reasonably apply force to remove a child from a classroom or secure compliance with instructions, but not merely as corporal punishment. Coupled with the requirement that the conduct be corrective, which rules out conduct stemming from the caregiver’s frustration, loss of temper or abusive personality, a consistent picture emerges of the area covered by s. 43.”
http://www.canlii.org/canlii-dynamic/en/ca/scc/doc/2004/2004scc4/2004scc4.html?searchUrlHash=AAAAAQAac3BhbmtpbmcgInNlY3Rpb24gNDMiIDIwMDQAAAAAAQ&resultIndex=1#
A relevant article on this issue: http://www.lfpress.com/2015/12/23/cornies-let-spanking-legislation-stand-untouched