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