Many charities are now moving away from "data silos" and the concept of "owning one's records". Which is great news and about time. So the next time one of your users/colleagues/staff says to you, "I don’t want my contacts to be stored on a central database because I don't want anyone else to be able to contact them…" then this is the response I recommend you give them:
The fundamental problem with this is that if they don't store their contacts on the central database (and instead, for example, keep them stored in Excel) then, in actual fact, it will be impossible for them to stop anyone else contacting them - assuming that such contacts have - or will have - other relationships with your organisation which are already stored on the central database. For example, if your user is the events manager, then if any of their event registrants are also donors, volunteers, prospects, on other mailing lists etc and as such they are already stored on the central database, then how can the events manager stop them being mailed? No-one using the central database will know that they are also on the separate events spreadsheet. Moreover, they will probably need to be contacted sometimes by other users anyway.
Of course, you could introduce a system whereby you check both systems for duplicate records and do file transfers between the systems, and thus flag the central database with some sort of mailstop, but that can be potentially complex, unreliable, definitely time consuming, will invariably carry a cost of some sort (even if it is internal costs only), and it will immediately go out-of-date unless the routine is constantly repeated. And even then it isn't going to be definitely 100% reliable (e.g. because different systems may store name fields differently, have different coding systems, even have different addresses but for the same person, or their data structure may be updated in the future without the other system being aware of it).
The best way to manage this situation is to store all such records on the central database and then to introduce policies and procedures to manage a structured communication policy. And, if necessary, appropriate security to ensure that only appropriate staff can view/update specific records or entities within such records.
In addition, more and more, organisations are understanding that the concept of "my records" is not helping the charity holistically. It is against the central ethos of CRM and the benefits that can bring. Of course, particular individuals may need to be managed by one/some specific staff, and relationship management should be at the core of any system and CRM (SRM) itself, but it is equally or even more important that NFPs do know all their constituencies and the people who connect with them. The days of individual data silos should, thankfully, be numbered.