‘The AA groups themselves ought to be fully supported by the voluntary contributions of their own members.’
If I am passing through Banská Bystrica and go to a meeting, I do not thereby become a member of that group. Nor do I cease to be a member of my home group, for which I remain responsible along with other group members. I thus contribute financially only to my own group. Group announcements helpfully quote this first line of the long form. Whether visitors and occasional attendees understand this and refrain from contributing to the pot is up to them. Since, in most groups, everyone pops a penny in the basket, even visitors, insisting that only group members contribute can come across as officious. Under the general principle underpinning Tradition Seven, each person is responsible for their own reception, understanding, interpretation, and application of incoming information.
When a group is dependent for its content, for its service, for its financial contributions, for its spiritual welfare, and for its culture and robustness on its own members, rather than on those who happen to be passing through or on irregular attendees, it acquires the character and strength of the spiritual entity it is intended to be. It can then survive even without such visitors. It need not post constant adverts online or publicise itself. It can take an unpopular approach (for instance focusing on the Steps and Traditions and being less interested in drunkalogues and ‘getting current’) without fear it will be unable to pay the rent. In short, it is free to follow its conscience. A few quid, euros, kronor, doubloons, or florins in the pot, split between even half a dozen people, is quite affordable and is dwarfed by the great changes wrought in one’s life through the sobriety it facilitates.