I trust most of the wrenches at my LBS, but last summer I bought a new bike for my wife for Mother's day, I was riding it around on some grass, checking it out, and the handlebars were loose! When I got it home I put a wrench on it, and found some other loose stuff.

I like my LBS, and I trust them mostly, but I guess you never know. I don't know who put that bike together, maybe they were having a bad day. I always check my own work twice, and someone else's work at least once. Sucks to have parts falling off a moving bike. trust no one but yourself when it comes to your safety