Answer:
I think this would not have been effective. I would recommend someone to ask the officers for a warrant and list their constitutional right to have the right to privacy.
Step-by-step explanation:
This question seems a bit variable depending on who you ask, so this is my opinion. When I read the word "assertive", it sounded like instructing the police in a more dominant manner. In general, it seems like the police will get more frustrated if you do this. Instead, I would bring up the fact that they need to have a warrant before they check my car because it's my constitutional right. Also, this is big, please video! There is no harm in taking videos of police doing work, so this will provide perfect evidence in the future that the police were illegally searching.
Again, this is my opinion, and other opinions are very valid. Hope this helped.