Except you can report that and they'll get punished

https://ised-isde.canada.ca/site/measurement-canada/en/file-complaint

Pints of draft beer Consider the following:

A pint contains 20 fluid ounces (568 millilitres) in Canada.

• The limit of error for 20 fluid ounces is 0.5 fluid ounces (15 millilitres).
• The foam (head) is not included in the measurement.

What you need before you start

In order to process your complaint, we will require:

• your name and contact information
• the name and address of the establishment
• information on how you have attempted to resolve the matter
• a photo of the menu or advertisement showing the quantity claimed to have been dispensed, if possible
• the sales receipt, if you have it