3Saints -- union or not, union contract or not, those employees were still, under/thanks to Texas law, at-will employees ( http://www.article-3.com/why-lie-in-texas-its-good-business-914548 , https://www.supreme.courts.state.tx.us/historical/2014/apr/120626.pdf ) -- given the terms of the involved CBAs, that they themselves were terminable for any reason, it's clear that it wouldn't have made any difference if the promise had been (or indeed was at some point or other in some form or other) in writing