Registration IDs can differ after additions

The newer registration structure supports an initial registration plus additional registrations in a group. The school registration list excludes grouped additional rows, while activity guest links use the base attendee's registration ID. This can expose a different related registration ID in an activity view. Different related IDs alone do not prove an error or a successful addition. Support should inspect the group, initial registration, guest/activity tickets and related payments before merging, deleting or charging anything again.