I'm pretty sure that scientists don't think they know everything. What leads me to believe this is that they keep building theories and doing experiments.
That's not exactly the way the word "theory" is used in a scientific context. I'd say the scientific use of the word is more like that in "music theory". It's not intended to imply a lack of confidence.
Looks promising. Trying to alter the workflow of people wanting specific content they can both get illegally and legally.
If in the warning there are direct links to the exact same content on the legal services this could start a wave of more and more people using the legal sites. Since it's that easy to switch.
That's exactly it, there is much more physics to discover and count in. People always think they know everything, at every point in history.