So what if he is 18, 26, 30? Racing at the pro level age should not be a factor. Sometimes runners run their best when they are you (i.e., Webb). And we all now the older you get the slower you get. For example, if Rupp were to race Hailie (who looks ancient by the way), Hailie would likely destroy him. So sometimes this whole age cheating stuff does not matter. Is Hailie reversing and is younger than he actually looks - he is more likely older. And I bet Ed Whitlock who is older than I probably ever will be could beat 99% of the people posting here.
When you race it should be about the clock. No doubt Rupp is a great runner and I expect will be getting better across a wide range of distances (I mean I did not expect his indoor mile from a guy that has proven to be world class at longer distances), but what if some new protege a year younger than Rupp beat him in a race? Would everyone say he's lying about his age?