I wonder if the court is looking at this sorta like a prenup. Common law marriage considerations might also come into play.

I can remember stories of couples considered married because a man took the woman home to his house and kept her for the night. That story might just be something young men are told to scare them into taking women somewhere else.

Another story about a man takes a woman to his house for the night and she refuses to leave. He has to legally evict her. Once again, don't know if true.

Casual sex in cars and hotels might be less legally binding.