If you want to cause trouble for Loblaws, don't shop at Loblaws and other chains of theirs. Willingly giving them your money, and then performatively "retaliating" by making the life of the minimum-wage employee (who would be here either way) slightly harder is completely useless as a form of protest. This feels like a rationalization for not taking the cart back by trying to hand-wave it to some large systematic actors. But the whole point is that the shopping cart choice is always a hyper-local choice. It's only about you, other customers and the people working at the store, not some distant megacorporation.