It looks like wallace doesn't care about kolabInvitationPolicy attribute.
I've added atribute to user LDAP object:
and send invitation, nothing changes - the invitation is delivered to user inbox asking for manual action.
The same applies to resources: no matter what is in LDAP, invitation are accepted by resource if there is no conflict.
The issue was tested on CentOS pykolab version pykolab and wallace being 0.7.14.
The same issue is reported on Debian Wheezy (7) with pykolab and wallace version 0.7.24-0~kolab1