You are curious... And you're not doing much to sway the people on here that think you're a management troll, but I'll entertain your question.

Empirical evidence and precedent. From my observation they haven't been enforcing the training contract. You can't establish a history of not enforcing contract language, it sets a precedent. This pilot group knows too well how powerful precedent can be in contract law. We've lost multiple grievances over violations of clear contract language in our CBA because of precedent. We didn't get the grievances filed soon enough and established a history of allowing the company to completely violate that language, we allowed the precedent to be set and precedent came back to bite us in the arse during arbitration.