I followed a link from an ESL website to an article claiming to be a guide by a paedophile teacher in Korea on how to seduce underage girls. The link had been posted by someone who was shocked and outraged, but thought that people should know about the danger. In reply, someone else suggested that it was most probably a posting by a nationalist attempting to denigrate ESL teachers as paedophile fifth columnists. The poster argued that the author had supplied a translation and made a number of mistakes in English. I cannot comment on the quality of the translation, though don't see why the author couldn't have learnt the language, especially if he had stayed there a long time. The English was full of mistakes, but they were the kind of mistakes that a native speaker could make when typing, and the ESL profession has many unqualified teachers whose grasp of the language is not what it should be. On another forum, I saw a case where a teacher had been accused put down to police corruption, which could be true as it was in a notoriously corrupt country.
Whether people defending the teachers are right or not, there is an issue of unsavoury characters coming into ESL because it gives them many opportunities. In over twenty years of teaching, I have only had a police check run once, and that was inadequate because it wasn't international.
There is a real risk, especially in areas where all that is required to get a job is to be a native speaker, that such people will target ESL. However unpleasant it may seem, it is something we should be aware of. I know of one case where a teacher died and the people clearing out his house came across his porn stash and were shocked to find out the truth about someone they had known for years. I shared a staffroom for a year with a paedophile and had no idea, though I imagine he hadn't managed to get up to anything that year, and only found out when someone wrote later from another country, where managerial care was minimal and he felt freer to act.
Two in twenty years is two too many, and I am currently living in a country where they play videos about the jail sentences for child abuse in the airport as you arrive, and can't help wondering what's happening here. There is a huge explosion of language schools here, some of which only require the teacher to be a native speaker, with a transient population of backpackers and travellers. It wouldn't be that difficult for a child molester to get a job here. There are arrests every week here of foreigners coming here for sex with children, and someone working in a school would be an asset to increasingly organised sex tourism operations. There are many areas of the ESL world which are bandit country, and such people may well thrive in them, and no matter how tiny the minority of the enemy within, anything above zero is unacceptable.