If you're looking for a quick fix for very minor scratches, then what about liquid bandaid? (Basically medical nail polish.) It often protects better in tricky areas like knuckles or fingers, especially if you expect to wash your hands. Sometimes you can combine the liquid bandaid with the regular one for extra protection. (The liquid bandaid can be rubbed off, and water can get through the fabric bandaid.)
As for the 3M Nexcare, you do need to form a good seal with the skin. If so, it will stay there for days, and you can even shower with it. Because it's so thin, clumsy fingers can result in a poor seal. Then it will come off like anything else.