Tugboats to Deepsea Union

I have been sailing on nearcoastal/ offshore tugboats as an officer but want to eventually explore the offshore unlimited side (I still have a third mate unlimited from my days at the academy). However, I have sailed as a mate as a member of USW, MMP inland, and currently IBU. I noticed on the MMP and MEBA deep sea applications it asks for previous/current union affiliation. Will my past membership In these tugboat unions disqualify me/ be an issue for me if applying? Could I be a current member of my tugboat union then withdraw after I have a job in the offshore union? Has anyone transitioned from a tugboat union to an offshore union like this before?

PS I know the industry is down right now, and I’m just collecting info for future reference for when or if the industry improves. Just curious is all