I think you misunderstand
@St***
, it's real visa/extension stamps from real immigration offices by real immigration officers. There is a clause in the Police Order concerning visa/extensions and it says "or at the discretion of the issuing officer" that means they can issue any visa/extension they want for any reason they want whether you meet the requirements or not.
Those visa/extension stamps are real, they're in the immigration database and people are indeed allowed to stay here on them..