I don't know the specifics about Ferry Beach (ironically, it was my first ever find!), but some land managers would consider any cache in violation of Rules 1 and 10.
On the other hand, there is a lot of support for Geocaching. Pat McGowen, then Maine's Conservation Commissioner, listed Geocaching as one of the activities encouraged at Maine's parks when a few local cachers were recognized as "land steward's of year" by the Androscoggin Land trust!
One thing that really irritates park managers is when hiders place a cache with out permission or with permission from the wrong person.
The farmer gave permission to place the cache in the field, but the bull charges.