BIP-110 and Bitcoin Knots is already huge number of Bitcoin node runners with lots of knowledge and expertise. If an attack is noticed the word will spread immediately. The Bitcoin immune system is working.

Yes we just point it out so we can react quickly if that happens. Thank you.

BIP110 does not protect against it until activation.

Much clearer now thank you Luke. For noobs like us; signalling literally means: 'declaring that you will run node/s implementing BIP-110 when the time comes' So even if we are currently running Knot-BIP-110 version, no actual filtering is happening until activation. It's a declararion of intent at this stage.