I don't know what machine you're using and how big your design is but bag "pockets" vary in size and can usually be embroidered if the design is small enough. If I was concerned about someone thinking that the wrong side was embroidered I would consider embroidering a small design such as a mongram on the pocket side in addition to the large design on the other side. Or, ask your customer if embroidering on the non-pocket side is a problem. If I tell a customer I can't do something and offer a different solution they almost always go with my suggestion.