Well when i lock the ipad it goes to sleep. If i wake it up right away, it stays on wifi. However if i wait about 20 seconds plus, the ipad is on 3 g. I have to wait about 4 seconds for it to turn to wifi. Im worried because when im not using my ipad ill get mail or notifications and that will use up my data. However the weird thing is that if i stream music or download an app and put my ipad to sleep, it will stay on wifi. Suggestions to fix it or is this normal.