I go both ways.
Generally, I’m a walker. I’ll go to the bathroom, get some water, or just pace around like Rain Man. I’d rather think about my own game than watch my opponent boom or beef. And I love coming back and seeing an empty machine.
If I don’t know the game, I’ll always stick around so I can watch my opponents play.
It seems like there are more watchers than walkers, in my experience.
Same here, both, depending on the machine, my opponent, my mood and the tournament situation. Note I have a third alternative - - watching a different match in progress, especially if I think I might be playing that game later.
Watch as I AM a luck vampire 
I walk if I know the game rules well, and have played this particular copy at least a handful of times. Even more likely to walk if I think the player might blow up the game…I don’t need to be there for that.
Otherwise I watch.
Generally a walker unless I feel I have something to learn by watching. Watching for the sake of watching does me no good because I find it better to only focus on my own performance.
If there’s a place to sit nearby I sit there and watch the dmd or score display from afar. I don’t want to be gone and my group wondering where I’m at from wandering.
I’ll walk away when someone starts a multiball
I don’t go anywhere. I just stay with the group and talk and have fun. It’s what I’m there for. I don’t watch the game like a hawk or anything.
Maybe that’s a lie. I’m usually tapped on the shoulder as soon as my ball is done and I’m running around making rulings or freeing stick balls and then when I wander back to my group usually they are there waiting for me with an empty game
I’ll typically get some solid movie watching done on my tablet each year at Pinburgh in between balls 
If there is a place to sit nearby, I will sit down to rest my feet. Otherwise, I typically watch or chat with a friend/opponent.
I don’t like to walk too far away as I always find it annoying when it’s someone’s turn and they are nowhere to be found, and I wouldn’t want that someone to be me.
Watch if I need information about that game, otherwise wander but not too far. Watching someone else play can consume energy as my mind will still ‘play’ the game and want to make shots… if I know the machine well I save that energy for my own game.
Watch if I’m not familiar with the game and walk when they start blowing it up!
Playing in a 4 player with Keith, Bowen & Zach you’ve probably got time to watch a whole box set between balls
I like to watch, but with my leg issues (NIB hip installed in September '18) I find myself hunting for a place to sit more often than not.
What’s your genre of choice?
I was binge watching Sense8 a couple of years back until the giant orgy scene popped up out of nowhere . . . yikes!
I’ll typically blow through whatever I have on DVR first, and then it’s all about what’s out. A couple of years back I got through a season of Black Mirror. Another year was just random movies. We’ll see what this Pinburgh brings! 
Suggestions:
I’m too short to watch so I walk
^ this (replying to @PinballNarcissist)
I’m always a watcher, because even if I know a game intimately, there’s always information to be gained - how are the flippers, the rubbers, the kickouts, the tilt… tons of data can be gleaned by not playing that helps make better decisions when playing.