Shamed soldier Gareth Walters ran away from paedophile hunters when they confronted him in Newcastle city centre.
The 38-year-old turned up at Central Station hoping to meet a 13-year-old but had fallen into a trap set by Dark Justice.
When faced by the vigilante duo and their camera instead of the schoolgirl he had hoped for, Walters made a run for it but justice soon caught up with him.
He was later arrested at his home and told police he only planned to warn the fictional youngster about the dangers of the internet if she had shown up.
The court heard Walters was dismissed from the armed forces in “disgrace” after he was given a 21 month jail term at a court martial in 2013 for wounding and deserting.
“You recognise, in fact, in your state, you were the danger to that young person, had there been such a young girl.”
The judge said Walters had served his country at a time when he had mental health difficulties and now needs help to control drinking and protect the public.
He has been assessed as posing a low risk of re offending.
Jamie Adams, defending, said since his arrest Walters has sought help and therapy for his ongoing issues, which has had a positive effect, and he has been in no trouble since.