It is important to note that there are two ways to get screwed by this. One is if you lied to your employer and they don't know (or you think they don't know) that your cert is fake.
Almost worse is if your employer does know your cert is fake, because many (see above post about EF Scum) will choose to turf you themselves, which will probably be more effective at forcing you to leave the country than SAFEA finding out and doing something.
Also, there was a guy in town recently who got turfed by SAFEA for work outside his contract. People should be aware of what their contract allows - and does not allow - them to do, and don't do other stuff. If you need more money, your school can possibly arrange tutoring that is somewhat more legitimate than private.