Inviting people you know to “stand beside you” and cut line in grocery store

The other day I stopped at the Dollar General store where I live (super small town- we have a DG, small family owned grocery store, and a gas station) I stopped for something I needed for dinner (2 things). The store was super busy, a line of no joke 15 people with one cashier. I got in line after grabbing my stuff, and while I’m waiting in line (with 3 people behind me at this point) the girl in front of me notices her friend walking to the check out line with a cart full of stuff and invites her to stand in line with her in front of me and everyone behind me at this point as we’ve all been waiting our turn in line. I couldn’t help but think how damn rude. I could see if she had a couple things but she seriously had a whole cart full. Do you think this is rude too, or acceptable?