That is one of the great attributes of a self-indexing progressive press that has the right features on it, like a Dillon 650. You literally can't double charge the shell unless you've got your powder measure messed up or you take shells out of the shell plate and move them back to earlier stations.
And, with at least .223 shells, there are a lot of good loadings that take up so much case space for powder that a double charge is pretty obvious because it's overflowing the case. Kind of hard to miss. In fact, I don't think there's ANY .223 loading that would allow a double charge without a considerable spill, and my favorite loads almost completely fill the case anyway. A dangerous overcharge would be easily noticed and in some case, I'm not sure it's even possible! Win 748 powder, for example, is pretty bulky for its grain weight, and some common .223 loadings with it take the powder into the neck of the case.
CJ