That's a legitimate concern and there's always far too big a portion of members either too weak or too apathetic to take a stand or at least get engaged in the process, but I do think there's at least a decent chance that there will be a far better voting turnout for this "Tentative Agreement" than the utterly pathetic total of around 65,000 total that showed up in 2013.It is going to pass because most people are too lazy to vote on something that is very important. Then the Teamsters vote for you and they want more dues money coming in.
I can't speak for other areas, but in my building nearly all the full time hourlies vote. I have never not voted on a contract and cannot understand why so many would neglect to do so. There's not many, if any, rational arguments to be made for forfeiting one's best chance to improve conditions regarding the workplace.