First let me say I am sorry that you were cited for this. I personally would not hold it against you or consider you some sort of bad guy.

But I wouldn't be confident about anything. This is a double edged sword of sorts. The law is the law and if I am correct, as in IL, it probobly says that you must tag your kill immediately upon harvest. Sure if you didn't walk up to the down deer you don't know for sure you even actually successfully harvested, so there is that. But the law might say something about making every effort to retrieve. (IMO allowing the deer to fully expire without spooking or running him off IS the most ethical thing a hunter can do, and most likely give a hunter the highest chance of retrieving it.)

I think if you were to have remained nearby and waited and then approached the deer that were down, tagging them upon contact, this would have been avoided. I am not judging or saying anyone did anything wrong - or right.

IMO the CPO's position is absolutely going to be that by a hunter leaving a shot deer laying with the tags still in his possession the hunter might be tempted to either shoot another "easier to recover" deer or a bigger deer and leave the other unrecovered. (And I have seen that happen.)