Before I went to work in SK, the SK government did a background check on my credentials to make sure I was who I claimed to be. This check took about a week, and involved my sending my actual degree and TESOL to the school I was going to work for. The school then submitted my documents to immigration. After the immigration office gave me the O.K., it sent my work visa to my school, and the school then sent it off to me. The school's name was written on the visa, so I know it was all legit.

You shouldn't try to pass off a fake degree in South Korea. You won't be able to get the 3-month visa (that will later be extended) that will allow you to be legally employed there.

Sure, you could possibly find a school somewhere that will allow you to work on a tourist visa, but you'll risk being deported, not to mention you'll be constantly looking over your shoulder wondering when you'll be busted. To top it off, you'll have to fly to Japan on occasion to renew your visa.