The advice provided in the original article is simply not sound or based on any data that would lead to better hiring decisions, regardless of the size or scale of the business. Surprising a candidate shows what exactly? It shows a person interviews well, nothing more. Unfortunately, skills in interviewing for jobs is not a skill that is useful in any role.
What does provide a lens into skills and potential for success in a role? Asking detailed open ended behavioral questions and using techniques such as STAR to understand exactly what a candidate did and how they performed. And this approach is highly predictable, based on results not just at Amazon, but the numerous organizations that rigorously apply these techniques in their hiring processes.
As a soloprenuer, I would be even more cautious of ANY hiring tactics or strategies that are not based on evidence. The risk of a poor hire has much greater impact. The concepts I shared in the reply are ones I have implemented as a startup founder, have applied to startups I have worked at, and have used in large organizations. Why? Because it works and because it is fair to candidates.