The TRE signs the lcense but doesn't the paperwork go to the Regulatory Authourity of the issuing country.
Of course the paperwork goes to the responsible CAA, but does anybody actually verify this? I don't think so... so basically anybody with a photocopier and half a clue to what goes on inside a cockpit can bluff his/her way into a job.
The only thing that gets checked thoroughly is the National Disclosure stuff (because "we can't let the terrorists win"
) but I guess that this can be circumvented by giving bankrupt airlines (plenty of those around!) as past employers!