Since UASF doesn't look like it'll go very far, I also doubt they'll bother with that.
Oh, UASF will go very far believe me!
Oh yeah? They got 80% hash power?
It doesn't matter how much hash power do they have. What does matter is that nobody in their right mind wants their bitcoins turned into chinacoins!
So how many exchanges are on board with UASF? How many wallets?
UASF has neither mining majority nor economic majority. I wish it was different, but that's the reality.
Exchanges and wallets doesn't matter as the number of their customers doesn't matter. What does matter is how many network nodes are UASF activated and relay or refuse to relay txs from those exchanges and wallets.