I think the fact hat we have a discussion about Scouts (all ages) and geocaching is fantastic.
Just to throw my two penneth in, for Geocaching and Scouts to go forward hand in hand i think like most other activties we need to have a scaled in approach.
Carygang, I know you are working on a factsheet but i would suggest that it would probably need to cover the full spectrum of ages and give ideas on what can be done. For example a 'mini' caching game for Beavers to introduce them, a first taster of GPS's with a tresure hunt for cubs and moving onto GPS basic and advanced for Scouts and Explorers.
It's a new hobby that fits in well with the Scout programme and and such everyone everyone here can probably contribute to the setting up of it within Scouting.
Have a group travel bug, use it for the Group international bagde, geocaching can be a great educational tool as well.
Thats my "County Role" opinion.
Personally, I do have to agree that many cachers have taken time and energy to set up caches in such a way that they are not noticable by muggles, having 10+ beavers running around someones cache will certainly make it stand out. I would suggest, as others have setting up your own caches just for the beavers and maybe even cubs, let them have the fun of hunting the treasure with or without a GPS and clues and then exciment when they find it.