A Swedish pilot flew airliners for thirteen years even though the only pilot certification was no longer valid and for smaller airplanes. It wouldn't have been too hard to forged advanced qualifications on my old licence. I have to produce my licence and medical at every flight test and written test, but they are mostly just looking for the name and address.
Most employers just see a copy of the licence, because they either ask for faxed documents before an interview, or want photocopies for their files after hiring.
Mine is real.