Cutting in Line

[tech]

I'm at the grocery store, waiting behind 4-5 people in the self-checkout line. Just as a spot opens up, two guys about 16-17 years old come walking up and take the spot, bypassing everyone waiting in line, smirking as they walk up. It is clearly intentional on their part. No one else in line is going to say anything.

(a) Is it worth making a scene over this?
(b) If so, what's your opening line?

Results later.

Note: Each of these guys is about 5'8", 120 lbs. I am about 5'11", 230 lbs, 13% body fat.