Whoa whoa! I can legally carry at work. No worries there.
1. Locking up the lot at night
2. Picking up or dropping off customers
3. Out back of building (more or less a large alley) face down in a vehicle with a loud shop-vac running.
4. In the wash bay with 2 compressors, and a pressure washer running while focusing on my job
Both 1 and 2 can be improved by your advice. However during 3 I cannot even tell when vehicles drive by, so a would be crook could walk up no problem. Finally 4, and this one infuriates me, you would think in a closed in building covered in employee only signs and an entire shop of people I could let my guard down a bit and focus on work. But the other day a dirtbag was looking for a guy I work with and got within 4 feet of me. No one else ever saw him, I definitely did not hear him coming, and if anything would have happened no one would have heard or seen anything.