i guess it makes sense that there wouldn’t be a consensus with regard to how people use it or about what is “proper” usage given it is just a service/tool, though in this small sample size it does appear that it is acceptable/accepted practice to reach out to/be solicited by, others without the expectation of introduction/meeting ever…though a former co-worker recently told me that linkedin actually doesn’t allow custom invitations to certain accounts or maybe that is a pro feature?