There are times when setting up for a shot is not an option. Take the annual family gathering picnic for example. 8 adults, 6 kids and a dog. Everyone is food-focused and no one is photo-op oriented. Also (as you can see on the left) no one is willing to stand still, even for a second.
This is why setting up for a shot is nearly impossible. Well, not impossible - strobes can be tied up (or gaffertaped, or spiderred) to trees. However this solution will provide harsh light. I was looking for something softer.
The obvious option is to shoot with no - trust good old available light. This is a good option and many great moments can be captured using available light. Yet, there is another option, such that will allow you to use off camera flash even in the toughest situations.