I was fooling about trying what the view would be like if I mounted my GoPro on the back of my board and I never saw it before but my Union Force bindings actually flex off the board... I'm sure it's just the plastic disc but surely that's not good???
I'm not up to speed on the GoPro yet but when I am, I'll post the video....
Many bindings do that, it isn't an issue. Some companies actually increase the amount of flex (burton, union, raiden/nitro) When the bindings have room to move it gives more "feel" to the board. It is the idea behind the NOW bindings (pivoting) Anyhow Unless the video shows something crazy it is a common thing and one of the reasons people prefer plastic to metal on their bindings.
If you want something with less flex try Rides with the metal frame. Nice bindings and less flex in the base frame. But I've never noticed better turns or pop from it. I love bindings with new flex patterns, Burton Genesis, Forum Republics. They feel better and responsiveness is still great.
I think that you want your binding to flex relative to the board from left to right so that it can match the curvature of the board, but you would rather that it not flex from from to back as this reduces responsiveness, (or if you do want that to happen it is on purpose as you want something to be softer or damper).
Think of it this way: if your bindings were completely married to your board, which is designed to flex, your board would have no-flex-zones.
In ie gineering terms, it would be a 2nd order discontinuity. In layman terms, you have a curve, flat, curve, clay, curve where it should be a curve all the way.
Thanks guys... Kaborkian, I getvthat.... Have a look at my other threads and you'll see I'm very much a noobie and seeing the amount of flexaural difference between the board and bindings did surprise me.