I agree there really is no safe time. That being said, all the crazies seem to come out at night, at least in my area. I prefer day clients.
Plus, when I work evenings, no matter how boldly and blatantly I specify in my ad that I DON'T do car meets, I get at least twenty people asking me if I can meet them in their car. Since it's 'after dark'.
Oh, and people tend to drink in the evenings, and that always brings out some fun clients.