Also if you're on Sprint ensure the "Sprint Connection Optimizer" is turned off. If it is on it will keep randomly turning your WiFi on. It is Sprint's way of trying to get people off the network and on WiFi.
Yeah, I already did that. It wasn't that. I think it's that Lookout security app from T-Mobile. It usually happens when I restart my phone. My GPS & WiFi turn on. It's so that if my phone gets stolen or lost I can pinpoint its location. But WiFi did turn on once automatically when it recognized a WiFi connection I had previously used at a friends house. I don't know how that happen.