I've never actually encountered one who didn't. Just like I've never been able to actually quit on Tuesday and walk into my next role on Thursday the way Hackernews told me "any halfway decent developer" should be able to do. They tend to ask about this sort of thing in interviews too and if you prove not to have the required background, you are considered weak and filtered out.

Anyways, checking happens often enough that the risk of being considered a liar and a fraud for claiming experience you don't have is high.