I am sure you are all doing this anyway but the committee have asked me to re-iterate that non-members and children are not allowed on any trips. (Including walks)
Non-members can attend a group as a taster before joining but this does not apply to trips.
The insurers thinking on this is that the risk from trips is far higher that that from a static group hence their ruling.
If a non-member wants to go on a trip then they will have to join. £15 is not much for a whole year.