He wasn't in the parking lot at the initial encounter. He was at the front door.
I've seen many voter registration drives like this. There's nothing wrong with them, as long as they don't try to promote a specific candidate, and they turn in all registrations.
In my state, registration is non-partisan. The only time a party is recorded is when you vote in a primary, so that you can't vote in another party's primary during the same election cycle.
When the registered person shows up to vote they are denied, since they have already voted absentee. They are given a conditional ballot that doesn't count, since the mail in ballot is already in.
Id the newly registered voter doesn't show up, nobody is the wiser, since the only ballot is an absentee ballot.
The Dems depend upon people they had to chase down to register, not showing up to vote. They also have no problem if they do, because they have already voted absentee.