Yeah, I am always on my own when I line up. I'm usually picking up shoes for my clients or my dad (who works on-call shifts so can't camp out) or my boyfriend (who works 14+ hour days so can't camp out).
The first time a guy picked me up and moved me then let five of his friends get in front of me, I tried to stare him down as best I could. When that didn't work, I asked him who the eff he thought he and his friends were and what the eff they thought they were doing. When he said "Simmer down, pipsqueak!" I had it, so I called the cop who was monitoring over and told him what happened. He set the guys straight. After that, I've always kept pepper spray on me (a pink, glittery one) and I pull it out when I feel someone try to pick me up. I also make it a point to wear some sort of spiked heels and I am not afraid to make sure a guy can never have kids or get hard again. Some stilettos are meant to pierce skin.