I understand your intention, but it is only necessary if you are expecting the company to be evasive or dishonest with shareholders, and even then, the success of your tactic relies on you being able to read the body language and interpret it accurately. Good luck with that. On the flip side, as your approach ensures that the question will come as a surprise to the panel, it may not allow the company to gather the information required, or to carefully consider all aspects and implications of the question and to answer in as detailed and accurate a fashion as if they had some advance warning. Personally, if I was so worried about not getting as straight answer from the people managing my shareholding that I had to resort to this sort of interrogation approach, then I wouldn't be investing with them in the first place. Lastly, the problem with questions without notice is that the person naturally becomes defensive and plays it safe with their answers because they are having to think and speak off the cuff. Fine for straightforward yes/no type questions, but if you want detail, give them time to gather it so it can be communicated fully and accurately.
(20min delay)