One of the reasons folks live in the bay area is because of the consistent good weather. People love to be outside. At times, its not too hot or too cold so they want to be outside. 

There is a big difference when you are setting up an outside or inside event. There is way less to think about when you are setting up inside. One does not have to think about the weather when you are inside. The main concern about being inside is how close are they to a power source. 

Outside, one has to think about the power source also. Does the dj need a generator or do they provide it themselves. How much extension chord do they need?

Also they need to provide shelter or will shelter be provided for them. The sun can damage gear and also prevent gear from working correctly. I learned that certain brands of speakers can not handle the heat and turned off with the heat when playing at an event in Gilroy. In Burbank in southern California the controller would turn off and one when it got to hot. 

 Since outside has more space of course then indoors the dj has to consider bringing more speakers to cover a larger area. Would 2 speakers work or would a few bigger ones be needed? For my main speakers I carry weather resistant covers to play in the hot sun or in the rain. 

So in the outside events, make sure your dj carries extra gear for the unexpected. As a client, it makes it easier to get them close to a power source and provide shelter for the dj and the gear.