I’ve used self-checkouts in Canada and in The Netherlands. The ones here in Canada are just like the miserable experience you describe. Especially the weight sensor and the machine complaining. In The Netherlands I never had that issue (even with a second person helping me). I’m convinced companies have just turned the anti-theft settings up to aggravating false-positive levels over here.

At least where I’m from (Canada), bread comes with a clip holding the bag shut, not a twist tie. “Re-using the clip” means the clip the came with the bag. You can see that it’s a different shape in the picture. This would be the equivalent of re-using the twist tie, if that’s how the bread is packaged where you live.