Yeah, you need it to register, but you emphatically do not to submit a ballot, which is the part that actually matters.
How do I know this? Because every time I have ever voted in NYC, I have walked into the location, given them my name, and voted. There is no check.
This is not some complex security flaw that requires great ingenuity to exploit.
You have to be completely ideologically blinkered not to see a problem here.