Interrogation techniques

Scene: Saturday, my mom's house. Pete and I are babysitting Gerise's kids and our own.

Pete: Harry, did you push Ernie down the steps?
Harry: No.

...a few minutes pass....

Cindy: Harry, how did Ernie fall down the steps?
Harry: I pushed him.

several hours pass.

Cindy relays story to Birger.

Birger: See, you don't need waterboarding!