While PGC has been locked out of groundspeak's API, I have been looking at what facilities PGC provides to non-authenticated users. There appears to be some inconsistancy, which seems more of a bug than a lack of a feature.
While non-authenticated these menu items are available:
Overview / Infographics / Top logged / Top finders / Top FTF / Top hidden / Logs per date / Hidden per date
It seems odd to me that Top logged does not require authentication but that top anything else does. Lonely Caches would seem to use the same data set as Top Logged, Top elevation uses less groundspeak data. If you want to force people to authenticate (eg for logging access) provide what you can but maybe deny the profilename field to non-authenticated users. (And now it is sounding like a feature request!)
At some stage could PGC do a review of what access can/should be provided for non-authenticated users.