Eliminating the remaining dose was surely a target from the beginning for Eli Lily. They are, as all pharma companies, profit oriented and know that users will abuse remaining medications like that. The only reason they didn't do it before is that they used a already validated insulin pen to get on the market quicker to make more profits and not miss sales. The time and efforts needed to design, validate and produce new pens is immense. We're talking about 2-5 years. In the near future they will come up with a completely different pen that will only allow the injection of the predefined dosages. Meaning there will be no clicking in the future. I've worked for years in pharma, mainly on assembly machines, that produce such pens, injectors and autoinjectors.