I have found that grannies have a much higher understanding if the terms privacy and 'I have nothing to hide'

Right, they’re notable exceptions to a trend, aka outliers.

Why is reinforcing that stereotype important to you?

“When did you stop beating your wife.”

I never beat her. The question you were aiming for is "Do you still hit your wife?"

It demands a yes/no answer and thus always appears to be an admission of guilt. Your question leaves it open to answer any way you like.

Your answer still works for your formulation of the question, "I never hit her."

It's not that it's a true Catch 22, it's just leading and begs the question.