I placed a 2005 Maine Geocoin in our first cache, I didnt write down the ser.#, I just placed it as a prize for someone. Is this O.K.? Reading some of the posts I see that they are trackable and /or can be registered. Does this mean they can be used as a travel bug? How do you register them and what is the purpose? Any info. on these would be appreciated as I have one more to go in my 2nd cache, and one to keep as a collector item for myself. Thanks,,"Dave and Gail" the newbies!