There is an exception. If someone is handing out geocoin codes for DISCOVERY at an event, it could be that the coins belong to that person. Many people like to collect the different geocoin icons on their page. At Discovery tables, I often have a collection of handouts with a list of all my coins that people can take. This avoids having to sit down and go through every coin to identify & write out every tracking number. Usually, this is only done with geocoins. So if you see someone at a table at an event with a collection of coins, a good way to inquire about it is to ask, "Is this the discovery list for your personal collection?". If yes, then it is acceptable. If no, then Earth's above response would be a good response.
Thank you for clarifying this! We just went to our first event, #gbp2014 & met some very nice people who explained the trackables table to us and gave us their list of trackables to discover. I had never heard of virtual logging before and was sad to think I had done that! But it's nice to know that discovering in this way ( which they all were personals of these people) is okay! Whew!