very true.
The problem is if you have red flags after that.
The problem of Unreliable speed is that it is Unreliable. You don't know which speed is good. STBY ASI is as unreliable as any other speed indication.
From the moment you come to the conclusion that speed is Unreliable (which is the most difficult thing) then you trust no indication at all and manually fly pitch and thrust or pitch and flight path, depending on the circumstances.
If it happens at high speed in the middle of the take of run, well, it is a tricky situation which has not been foreseen in the procedure. What if you STOP and it happens that actual speed is very high and it is long time you passed V1? Then you will overrun the runway, that's what will happen. What if you continue? At what speed do you rotate?
there is no way to make a 100% safe decision. Probably in this case pilot instinct will make the decision. If the pilot feels that he can stop within remaining runway, he will stop. It he feels he will not, he will continue and rotate when he feels he can. And then apply the procedure