I believe in the past, the officers are managers claim was used for a company to declare null and void a contract with a union for the officers however, it was the mariners who chose to enforce that by going along with it. If marine officers want to be represented by a union, there in no LAW in the land that a union cannot represent them hence why the MMP, MEBA and AMO represent officers where ever the officers stand by the union. A company can try to bust a union but it is up to the rank and file if that will be allowed to stand. The workers have the right to call BULLSHIT on Joe Boss but rarely do even in relatively strong unions these days. You don't hear much about strikes anywhere anymore and it isn't because all the bosses are just the nicest people ever.
If a company which currently does not have a contract with an officers union wants their officers to sign some statement declaring that they hold with the company policy then it is equivalent to a loyalty oath but could not be enforced in a court however Louisiana being an at-will employment state, anyone violating an oath they took siding with the company would have little recourse if they were fired for later asking for union representation. Joe Boss is running scared and is trying to intimidate his officers now to toe the line and be loyal serfs. Joe wanting it in writing is what is telling here because in the past he managed to bullshit the workers into believing they were getting ambrosia instead of a shit sandwich. Maybe the mariners are waking up to realize that they aren't eating the food of the Gods any more but the boss's feces instead? If so, then good for them I say...welcome to the fight brother!
The only way to make a union in the GoM get standing is by solidarity across all trades and a massive walkout by all oilfield mariners. But Joe would always find enough scabs by tossing money at them and that is why you will never see a union in the GoM. The sad reality is that the mariners really hold the aces since Joe cannot hire scabs with the required certificates off the street anymore. He needs the workers he has because the USCG will not accept substitutes (or would they?) Sadly, though the mariners will cave as they always do and sign the loyalty oath believing that it is in their best interest to do so when in reality it is in their worse. This is why I always say the GoM is a backwards land and will remain backwards for the foreseeable future. Walk backwards, talk backwards, think backwards, act backwards, get stabbed in the back and ask the boss for another...what a world!