Every system that exists as a black box is more understandable with more sensing, not less. Our bodies are not special.
It's also ridiculous that the proposition goes like:
1. Doctor knows some tests will flag tumors or variations that look weird and that we shouldn't then go investigate all of them
2. Doctor shuts off their brain and will then investigate all of them by doing invasive procedures
Just knowing how many such variations there are and if they grow or not is useful information. But the doctors pretend like they are super smart before the test and super dumb right after.