If i'm going for work, or for more than one day, my MBP always goes with me. Usually have my iPad with me as well, but it will go on short, overnight trips even when the laptop doesn't. iPhone is always with me, because it's my phone.
It's a laptop, not a precious gemstone. When I go on lunch break at work (and I'm usually working in museums or convention centers), it typically just sits out on the table while I'm gone. I'm sure one day, I might fall victim, but to date, I've done it this way for 15 years, and no problems. And, I touch it with dirty hands, too! I've never quite understood the treating of a laptop like a historical artifact.