Yes, and the the thing is that most people are "on the border" - that is to say, little more than a product of their environment (speaking of their actions/attitudes, not their worth as people). If you teach an entire population ethics (assuming it's done well and everything that comes with that), you will still have your 5-10% of rotten apples, just as you'd have 5-10% who would seek out ethics on their own. The big difference will be in the 80-90%.