My brother an Engineer was in a nightclub about 2!in the morning when he met his flight crew. The 8am, departure.
No names no pack drill.
It happens.

Me? One beer then to bed. I'm boring though.

Back in my skydiving days we had an an away day/weekend near a seaside resort. We all went to the pub for dinner after the first day. Notably everyone stuck to the one or two beers, even the Skydivers the Tandem Instructors. Skydivers are not noted for their restraint.
Anyway next morn bright and early we sallied to the airport. Everyone was bright and bushy tailed except one chap the packer. I didn't know.
On an early flight there was a slot for a single. But as he boarded the brewery followed. I ordered him off, even If wasn't dangerous to anyone but himself. I wasn't having it.
He's still a friend and he thanked me. But he still drinks too much.

Unacceptable. Should have been reported if they were drinking.

Yes indeed 'Shamrock'. Neither I nor my brother have evidence they were drinking. My brother wasn't and I had no evidence. Ironic your username.....

There is no such thing as "exempting crew from security checks," only "exempting people who appear to be crew from security checks." The failure modes should be obvious, but I heard it best from a screener, in response to a crew member who was complaining, "Forgive me, but down here at my pay grade, I can't reliably tell the difference between you and the guy who stole your uniform and ID out of your car."