Apple's yearly developer conference should see iOS 8, OS X 10.10, and likely some hardware.
More iPhone Sightings
(click thumbnail for larger)
Portions have been blurred and scaled to protect the individual's privacy. The increase in sightings could be due to one claim that individuals lucky enough to have an iPhone at this early date are now permitted to use them in public.
An earlier photo which had made the rounds showed someone using the iPhone on a train.
Finally, a first-hand report was posted to our iPhone forums, in which the author claims to have used the iPhone himself.