For any such future requests, have the customer be more precise about what they actually want. 'Oil Finish' covers a lot of things, many of which might not be considered an oil finish depending on how picky the individual is. Tru-oil, for example, contains resins (aka varnish), with enough coats (20-30 are often done) it can look almost like a varnish or lacquer coating. 'Danish Oil' finish is similar, doesn't mean they are bad, but might not be what is being requested. For finishes which are strictly oil, I like walnut oil (for anything that might end up near food), polymerized linseed oil or pure tung oil. I avoid 'boiled' linseed oil (which has heavy metal additives), and pretty much anything else like 'teak oil', 'lemon oil', etc.
Thank You Kindly.