When your in a full blow tank slapper like in the vid, staying relaxed might help but that easier said than done. I've been there and it happens so fast an violently I was praying and holding on for dear life.

But staying relaxed and not manhandling the bars will greatly lower the chance of ending up in a full blown tank slapper in the first place. When accelerating hard over rough pavement and the fronts start to shake, LOOSEN up on the bars and stay on the gas. The front tire wants to fix itself (go straight), if your manhandling the bars when it starts to shake your only fighting against what the bike wants to do therefore amplifying the shake. The bars are for steering the bike, THAT'S IT, NOTHING ELSE and it takes such little input on the bars to turn the bike.

You should always practice being loose on the bars. Not only to prevent slappers but to be a better rider all around (Turning, braking, smooth etc..). I hate seeing riders with straight arms and locked elbows, it's the biggest give away that's a bad rider. Dampers are nice but make sure it's not just a band aid to cover up bad riding habits.