I think Charlie's second suggestion may be more useful viz. the ability to hide datasets existence from the eyes of the general user of the Gateway with the data provider proactively giving users/organisations access.
Since the stat agencies are requiring the use of the Gateway as a delivery mechanism, some LRCs are getting round the problem of refusals from individual recorders to put data on the Gateway (in a publically available sense) by creating datasets of these records and only allowing access to their partners. This is usually not the LRC themselves being difficult btw! As well as this case, there are other reasons for records being placed in "hidden" datasets, such as them being known duplicates of those uploaded by a national scheme (but perhaps not quickly enough or detailed enough for the stat agencies) or unverified as previously mentioned.
I don't think an assumption that records wouldn't be useful to others is ever a reason for non-public access datasets, and reasons of species sensitivity/environmental harm are probably in the minority.
It could be argued that the NBNG is not the best mechanism for this kind of non-public disemmination, but we are where we are and organisations have bought into the Gateway and developed tools to use the data, so the number of these non-public datasets is likely to increase rather than decrease in the short-term at least.
To debate with myself, I can see a reason for not hiding these datasets - the signposting opportunities that the Gateway offers for the existence of pertinent records to researchers and specialists. I think all the datasets mentioned here do clearly explain the situation in their metadata pages so perhaps the status quo is fine?
I think we are one of the "best" LRCs for putting data on the Gateway in the sense of putting a high proportion of our records on, but probably one of the "worst" compared to LRCs who only put their really super high quality, comprehensively verified data on. Regardless, I am concerned that records that fall into the categories above which we make available to partners offline will not be available to our national partners so will probably be uploading a "hidden" dataset soon of those records.
Teresa Frost | Wetland Bird Survey National Organiser | BTO
Other hat | National Forum for Biological Recording Council
(Old hats | NBN Board, ALERC Board, CBDC, KMBRC)