Hi,
what about putting the coins and the activation code in the zip pocket and altogether in the caches.
You note the tracking codes on a paper and leave that paper at home.
After 2 weeks or so you can look after the coins as you have the tracking codes and put a watch function on the coins if you like.
So the new coin owner gets an unactivated coin, has no problems with adopting the coin and can decide about a mission or putting the coin into his collection.
That would be a perfect gift!