95% miners have to agree, how are they given the choice to "agree" or not? By simply downloading the latest update or they get some voting mechanism in place ?
What if a rogue node fails to agree? Say some node alliance in a country, then what happens?
Some pools are signaling SegWit support, while others aren't.
By mining on a pool that supports SegWit, you inherently "agree" to it. Pools themselves can choose to broadcast SegWit support however, and all miners will automatically agree to do so.
I honestly believe some miners have no idea what SegWit is or why they should support it, which is why I think that only the pool owners can make the change.