I have shot at least 600 photos in one day. Usually my Pana GH2 runs up to one day on a battery, sometimes I have to change towards the end of the day. But, yes, not if I do not turn off. I cannot imagine that being a problem, my thumb turns on the camera as I start raising it, by the time it reaches my eye it is ready for AF.
Support bird conservation in the Caribbean: BirdCaribbean
Just moved to Barbados