For this network to succeed, every instance needs the exact rules required for its unique membership.
Offline operates the same way. A library, a dinner party, a nightclub all set different rules to serve their particular needs.
Diversity of policy is a natural outcome of diversity of people. Helping communities define and enforce their own boundaries is a core goal for IFTAS.
If some find guidance by referring to peer/trusted instances, great. If not, also great.