>>33832453 (OP)
If your ass denied me coming back in line you would be the smallest dick person in the world. I would stand there anyway. If your ass decides to make a fuss I'll act oblivious and wait for security to come over. This is the most pathetic hill to die on.
In a high trust society (Netherlands) people will even wait for you until you return even if it's your turn to scan. And if they didn't wait then they'll let you go right after them. Don't be a filthy low trust person. Make your environment better. Be the change.
Though I do agree that it's better to ask, but sometimes people forget, don't be an asshole