Hey @saylor, the idea that a URSF is somehow required is a rhetorical invention by BIP110 proponents. It shifts the burden from demonstrating broad support to claiming victory by default unless opponents actively fork away. That's not how Bitcoin consensus works.
We don't need a URSF because BIP110's mandatory signaling already acts as its own activation mechanism.
If it ever falls behind (even at 30% hashrate it will), it stays behind unless it overtakes the main chain. You can even experiment with this yourself using @OrangeSurfBTC BIP110 simulator.
And for anyone still worried, there's already a built-in solution: if a lagging BIP110 fork ever appears, you can simply invalidateblock its first block. Your node will never switch to that chain no special software or URSF required.