Do all your homework

Hello everyone. I have a question.

Regarding the following passage:

These days, best practice in driving calls for lower speed and the use of air bags and seat belts. After air bags were introduced, drivers and riders felt secure. Many stopped buckling their seat belts. This reflects the assumption, not based on best-practice results, that air bags do it all. But testing shows that air bags work best for those who also use seat belts. Therefore, seat belts are a current best-practice element in safe driving.

So we see that assumptions about future best practice are dangerous. In future-best practice research, it is essential that you avoid preconceived ideas, however logical. Do all your homework, including questioning assumptions.

Why does the author say "Do all your homework" at the bottom of the passage? Is it a kind of rhetoric intended to sound like a lecture to children? Does he honestly say that in order to achieve future best practice, we should do all the necessary things that seem painful?