VoId always follow Airtel like a slave. But this time, they have no other option at all. They are the ones who are badly in need of tariff hikes and if they resist this hike, especially when their master Airtel is hiking, then both Airtel and Jio will never join them in future tariff hike (so that VoId can die faster) as well as oppose floor pricing (even in discussion level).
Actually this tariff hike from Rs49 to Rs79 will back fire VoId more than Airtel, but again, this is better option for VoId than not hiking at all. This will be the biggest opportunity for BSNL to gain subscribers (for secondary connection), but History says, BSNL always love to mess up their great opportunities ever, so I don't have high hopes on them as well.