Securing cables in a crawl space?

My cottage is built on piers, and is between 1' and 3' off the ground. All the electrical cables were just lying on the ground; presumably for 40 years. Today I bit the bullet and stapled them to the joists.

Does that meet code, or must they be run through the joists like in a basement?

The cottage has been sold at least 4 times over the years, and apparently no inspector has ever noticed the cables on the ground. That surrely doesn't meet code (even 40 years ago) does it?!