It's not always newbies that get it wrong, I released a coin in February that was in a race, it covered almost 5,000 miles by April, then it was picked up and nothing happened for months. I sent a couple of emails to the cacher that made the retrieve but got no response. I finally got an email yesterday with apologies, my coin had been 'forgotten' about, my emails had been diverted into a Spam folder. It was just an unfortunate set of circumstances, if someone has a huge inventory of coins it is going to be relatively easy to miss seeing that a coin 'in the hand' has not been moved on. The coin had physically been passed to someone else and was only recently returned into the hands of the cacher who retrieved it in April - even that part I find confusing because there have been no discovery logs. Anyway I am told that the coin will be moved on shortly.
The other coins that I have lost have been my own fault, inexperience in placing caches, they were muggled and I don't believe they were taken for the coins, I believe they were too visible.
It is dissapointing to 'lose' coins, but if you dropped a fifty dollar note on the floor of the shopping mall, no one is going to rush home and log on to Where's George. If you put coins out in the wild you have to be prepared to lose them. If you decide not to play that game then you lose out on the fun that can be derived from seeing where your coins go.
We all make mistakes, some are deliberate, only bad Karma can come to folks who are mean enough to spoil the game for others.