I'm sure we've all had moments like this, where we're late for work or for class at school, and our first thoughts are "what am I gonna say?" Usually we make up some lame story, or if we're trying to be an honest and virtuous person we tell the truth. Either way we fear the punishment of our tardiness. Rex of course would tell the truth, even if he was crying while telling it. Frank on the other hand has no problem telling a little white lie.
A wise man named James E. Faust once said in a talk entitled 'Honesty - A Moral Compass',
"When we tell little white lies, we become progressively color-blind. It is better to remain silent than to mislead. The degree to which each of us tells the whole truth and nothing but the truth depends on our conscience."