Actually... he COULD have explained it easily... but he (and his idiotic Attorney General, Bill Barr) is too stoopid. Bill Barr, when interviewed about it, said, "I'm not familiar with the voting laws in all the states..." and showed everyone who didn't already know that he is a jackass that he is actually more of a donkey pit, as I call them....
Anyway... THERE was a way out of it. Mrs Media, in the primary election, applied for a mail-in ballot, as did I. We both got them and mailed them in on the same day. I got an email verifying that my vote had been received and would be tabulated on election day. Mrs Media, however, kept checking the web site when she got NO confirmation that they had received her ballot. All the site listed for her ballot was "Pending."
So she did the right thing: She went to the pols on election day, explained what had happened with her mail-in ballot, and she asked if it had been received and/or recorded. They couldn't find a record of it, so they gave her a PROVISIONAL ballot. She filled that out and handed it in to the election officials. What the means is that if her mail-in ballot was not recorded, then her PROVISIONAL ballot from election day would count in its place. SO... in that way, she SORT OF did what Trump is telling people in NC to do. Of course, he said to send in the mail-in ballot, and then go to the polls to see if they can vote in person as well. Not the same thing... but he COULD have said, "Oh, I meant they should file a provisional ballot just to make sure."
One more way to clog up the election process. Big surprise that Trump would do this, eh?