Answer: Denial of injury
Explanation:
Denial of injury is the term used in criminal cases where the actions of any criminal does not cause damage to victim of the case. As no hurt or harm is caused to the victim, it is requested from criminal that event shouldn't be counted as crime.
The crimes that are usually committed in this scenario are stealing, argument,unofficially borrowing etc.
According to the situation mentioned in question, Frankie and Johnny are using the denial of injury method as they state they only stole the car for driving and showing it off.They defended themselves by explaining that their act did not cause any injury to others when they were caught by police.