When stopped by police at a roadside spot check and asked to provide a breath sample:

When stopped at a roadside spot check and asked to provide a breath sample, it is a criminal offence to refuse. Under the Ontario Highway Traffic Act and the Criminal Code of Canada, drivers are required to comply with a police officer's request for a breath sample when they have reasonable grounds to suspect that a driver may have been drinking. This requirement is in place to ensure the safety of all road users by facilitating the enforcement of laws against impaired driving.

Refusing to provide a breath sample can lead to serious legal consequences, including fines, license suspensions, and even criminal charges, similar to those for impaired driving itself. The law aims to discourage impaired driving and enhance public safety by removing drivers who may pose a risk from the roads. Thus, compliance is not just a matter of choice but an obligation enforced by law.