I'm not sure about that. Possession of child pornography is a serious crime in most Western countries, and the courts don't really care about excuses, explanations, or the fact that the crime is victim-less. Actually, in most countries, even non-child porn that looks like child porn is illegal (drawings, computer-generated images, adult actors that look like children, ...).
There is no way that say in Germany today the police could get away with trying to induce and photograph a teenage boy's erection for a sexting incident. It is such a fundamental violation of human dignity. I cannot even begin to imagine the press coverage and criminal indictments of the people involved.
The girl's mother called the police, and it surfaced that the girl had lied about her age and name to the man, so he was found guilty but his sentence was 45 days probation only (no jail time) and an 120 day restraining order.
A search for similar cases in the U.S. surfaces: 10 years jail time, 38 years of jail time, etc..
I'm sure there's many places in the law where discretion is used by someone in authority to determine guilt or innocence, but it still frightens me when I see it.