With a certain charter airline I flew with in the 1980s it was standard to sit drinking the odd G and T in the crewroom whilst the cabin crew counted the bars doing similar at circa 4 am after a night flight and well before the office wallahs arrived.
It didn't do any harm and was a social way of ironing out any difficulties encountered during the duty - we worked hard and played hard.
The company had it's own transport to position/reposition back to base - manys the crew that arrived back after the ride back in, shall we say, a merry state.