I am particularly annoyed at charities or organisations once they have obtained you contact details persist in contacting you after you have donated seeking additional donations.
I have arranged a number of memorial donations to a number of charities on memorial websites for family or friends or made a cash donation at the funeral, and once the charity has access to my contact details have persisted on multiple occasions seeking further support. Especially around Christmas receiving cards and mailing labels in exchange for further contributions.
Now I donate cash only, or bank cheque and send anonymously. I can appreciate the strain some of the charities and 'not for profit' agencies have in funding their good works, but they would be best served in not putting off those who are already supporting them.
I often think an annual contribution to a philanthropic foundation to support your choice of "not for profit" agencies or preferred causes might be a better way to approach community fund raising. It might reduce the overall cost of administrative overheads associated with fund raising, ensure the bona fides of the agencies and their proposals given there is such an overlap of "not for profit" causes. How many donate without the knowledge of how the donation will be used? Would this make a difference on which "not for profit" received your support?
In the past I have had the responsibility of making a number of contributions to 'not for profit' agencies on behalf of my employer. Prior to approving the payments, I was required to review the spending of the previous year's grants. It soon became apparent in some circumstances, the funding was not being used as represented in their submission.