Refinish a guitar to prevent damage, and in doing so add several coats of penetrating oil finish? And if it doesn't penetrate, it's because there's already a finish there, so just add a bunch of stuff and see if the tone is improved? Are you daft?

Unless it needs refinishing, don't refinish it! Get a decent cheap guitar and leave the good 'un home, if you're that worried. But refinish?

Are you daft?

Bob