And then while thinking about this ... I reread my point 3) above ... that would reduce the pool block find rate, by making big hashers find less blocks ...
You'd wanna hope no pool is doing that and causing their own bad luck ...
Thank you for your careful thinking on it. We started with Linux at the same year.
The check need not be on every found block.
Spot checking could be sufficient.
Also could skip check unless luck is down.
If nonce is in a known range unsupported by some hardware, it may be a false positive detection, which would require a second check for that condition.
Weigh it against the risk that there is malevolent action decreasing your luck.
Maybe it is hard, so was the byzantine general.
Maybe not worth discovering, or maybe Bitcoin is worth it or will be some day.
Maybe there are unintended consequences that must also be handled.
Experimentation will also be needed. Making the detection nonce block indistinguishable from other work is also a challenge, or counterdetection measures may develop.
Maybe more thought toward this goal of monitoring for bad actors which is not adequate today, will be even more fruitful. Thank you for your contribution today and for not ignoring what may be an important problem to solve...