I hope the airline has got the business sense not to bow down to Islamist politicians. Banning alcohol in Bahrain would be suicide-that country gets millions of Saudi tourists per year who are drawn to the 'liberal' lifestyle in Bahrain. Take this away, and not only will Gulf Air loose business, but so will the bars, hotels, restaurants etc.
Bahrain will become even more backwater, and banning alcohol means that the government is adopting a more hostile, 'anti-Western' attitude that will scare off investors in an already fragile economic context.
Gulf Air relies on transit traffic. The low-yield passengers may not mind too much, but premium business will be hurt. Gulf Air will shift to being like Kuwait Airways, Saudi Arabian and Egyptair-airlines that are not taking seriously when compared to EK, QR and EY. The difference is that Kuwait and Saudi Arabia have good O&D from their airlines.
Bahrain OTOH is very limited in O&D. If GF loses its value as a hub, it will literally become as big as Bahrain Air.