I was a stay at home dad for two years when my son was first born. I was always twenty minutes late to class during this period because I had to wait for my wife to get home from work before I could leave for jits. Luckily for me, my instructor has always understood that family comes first.
I really dislike missing warm ups. As you get older they become a requirement rather than an option. Since turning 40, I'm much more likely to pull or strain something during training if I don't warm up properly.