There are many other sophisticated scientific methods that could be used:
authenticating art and artifacts
One word that I often use: provenance. Cards that have been altered don't have a history-- or at least a history that shows it wasn't altered. Of course there are new finds. However, as autograph expert Jim Stinson once said of autographs: “Authentic autographs have a history or sources. Forgeries do not. They just ‘appear’.” Provenance is one thing that is standard is the high end art collecting world that is not in baseball card world.
Also, common sense is always useful.