Its not about being a sheep and following.
Being a member of a union is about solidarity , unity and getting improvments on T&C's in the workplace.
Voting yes doesnt automatically mean there will be a strike it does however give the union reps a mandate to go back to flybe management and show the strength of the membership feelings and the lengths they are prepared to go to, ie having to loose pay (which no one can afford the wages are currently so poor) in the short-term to win longer term improvements.