Reasons for PMO Caches Groundspeak does not state a reason for PMO caches. However, cache owners have stated various reasons for restricting their cache listings to premium members, including:
Hiding cache coordinates from local cache maggots who have only basic accounts.
Using the audit log feature of PMO caches.
Encouraging others to buy premium memberships, or rewarding them for doing so.
Keeping the cache out of products like the Geomate.jr (which include preloaded cache data, and don't require a geocaching.com account).
Preventing search engines and unregistered visitors from accessing logs and photos posted to the cache.
Rewarding premium members with an FTF opportunity (switching off the PMO flag later).
Reducing the traffic to the cache, to reduce the maintenance required (e.g., replacing full logs, resetting on-site puzzles) or to reduce geotrails.
Slowing down the initial rush of traffic to the cache site, to attract less attention from muggles or to reduce geotrails (switching off the PMO flag later).
Limiting access to "serious" geocachers, expecting them to treat the cache/camouflage/location/contents with more respect.
Limiting access to "serious" geocachers, expecting them to know how to log trackables correctly.
Limiting access to "serious" geocachers, expecting them to post better online logs.
Hiding a mystery/puzzle cache that requires premium membership to complete, so basic members don't see it.
Hiding a challenge cache from basic members who might not understand the need to complete the challenge before logging online.
Hiding caches from local basic members who complain (e.g., about caches that are "too difficult" or that cost money to find).
Being curious about what it's like to own a PMO cache.
Wanting to take advantage of all the features offered to premium members.