I e-mailed Ranger Perryman concerning the impounded cache and also asked if
there is a legal way to place a cache on U.S. Park property.  Here is his
response.

Mr. Flatt,

There is no fine associated with claiming the impounded property. To claim
it you just need to contact me at (520) 733-5129 to set up a time to pick
up your property.

There is a way that a cache can be placed in Saguaro National Park legally
and that is to place it above 4500ft after obtaining a special use permit.
The problem with placing one under 4500ft in Saguaro is that we have a
regulation restricting travel under 4500ft to established trails to lessen
the impact on the Sonoran Desert Ecosystem.

If you plan to place caches in other parks you should contact them before
doing so because each park has different regulations.

Vince Perryman
U.S. Park Ranger