This is always disclosed up front. In this case, did the company claim they were going to pay out and then they didn't? Or did the company never claim they would, but the ex-employees are "demanding" it anyway?
In practice this just means that you can take two weeks and still get paid. You can forgo your vacation in some instances, but you still get paid out the vacation money. I used to do that when I worked part-time in college and was short of cash for whatever reason.
Ontario's rules - https://www.ontario.ca/document/your-guide-employment-standa...
That screwed me when I changed jobs last year actually and I lost 3 days of pay that I didn't take.
PTO that is earned over time, as part of your pay period, is a form of compensation to be expected.