Ruining the last trains home out of London on the Friday night and hurting people travelling home for Christmas. So basically, what will happen is ever more people find an alternative (driving), decide it's not too bad and stick with it. The passengers won't forget having their break ruined. Let's hope the RMT remember this when they have even less public support. And passenger numbers drop even more on SWR. Then again, it is clear the RMT doesn't care what the public thinks; we are just a hindrance to them as much as a weapon to use.
(I will probably Uber it.... so indirectly the RMT is assisting to kill off that other bastion of democracy and populist support, the licensed Taxi Drivers' Association.... (they are busy killing themselves in London by the insane pricing and closed shop mentality))