At all the voting booths I've been to in Canada it would be super obvious if you tried to stuff the ballot. Even in the latest Russian election it was dead obvious with many incidents being captured on camera. Why are people allowed to loiter around the box?

The problem is they have no protocol for better protecting the ballot box and responding to ballot stuffing attempts and incidents. If you're not going to protect the ballot box it doesn't matter what tech you use for voting.