Rebecca Smith and Mark were not wrong at all.
As soon as the car accident happened, Hank Clegg started to suspect something was strange. If Victoria and the kids could think of the cause and effect, how could he not?
But Rebecca Smith's false testimony was flawless.
If they didn't take extreme measures, it would be absolutely impossible to find evidence of the truth. Therefore, to expose Rebecca Smith's deception, they had to play along, falsely accusing the kids and Michael, forcing them to "flee out of fear for punishment," so that Rebecca Smith would lower her guard.
Finally, let the kids infiltrate behind enemy lines and secretly retrieve the evidence.
Hank Clegg had already said that he had absolute confidence in his children.
Every time he said to Victoria, "Their IQ is higher than yours," he really didn't mean to upset Victoria.
However, what the kids and Michael hadn't thought of was: as the saying goes, the cleverer you are, the more problems you face.