SOLVED! : on Solana Beach, California, USA, on 2014-01-31

Rightful owner has been found. Kam told us in reply to a mail we sent on April 21st.
On Jan 31st we received this message from Kam. He found a GoPro!:
“FOUND!: GoPro Hero2, Solana Beach, California, USA, on January 31, 2014. Have pictures of couple snorkeling somewhere tropical, not San Diego.

If you think that this might be yours, please send us a message with as many details as possible: What were you wearing when the camera was lost (colours), what were you doing, etc…. We’ll pass it to Kam!

Mr. G.