During the course of a DUI investigation, the police may make either a roadside demand for samples or a demand for samples back at the station.
The first test is a pass/fail result and only creates grounds for an arrest.
The second involves the determination of your blood alcohol concentration and could lead to charges being laid.
If an officer makes either type of demand, you are required to provide the sample as requested. If you do not, you will face a refuse charge. The charge exists whether you refused to blow and made no attempts to do so, or if you attempted to provide a sample but for some reason the device could not register a proper sample.
It would then be up to you to show that either your intention was to provide a sample, or that you have a reasonable excuse for not doing so.
Refuse to provide a breath sample—whether it is at the roadside or at the police station—has a mandatory minimum penalty upon conviction. This penalty is the same as the penalty for being over the limit. If you are found guilty of refusing to provide a sample, the Judge is required by law to impose a minimum sentence of:
$1,000 fine (which is subject to a 30% surcharge);
1 year driving prohibition
The Ministry of Transportation will also automatically impose mandatory effects on your licence:
A concurrent 1 year licence suspension;
The requirement to complete the "back on track" program to regain your licence;
The installation of an ignition interlock device as a condition on your licence upon its return