That's what a long courtship is for.
It's still a lot different from marriage. If you're married, you're going to have to live together, and the two of you may easily have incompatabilities that a courtship, no matter how long, did not bring to the surface.
I'm not knocking somebody for going about it a different way. But in my view, if there are going to be problems, it's best to find them out if you can before you're in a situation which requires lawyers.