In post Christendom, as I have often argued, the Sunday morning gathering is essential, buts its very character changes from the ways we met in Christendom. It is no longer structured to attract seekers or non-Christians and evangelize them. It is no longer put together to attract Christians wandering away from other churches. It is instead formational, it brings us corporately into the practice of encountering God and being transformed by that encounter for life and Mission in Christ.
Such a gathering does, by its very nature, becomes somewhat inaccessible to visitors because it's a community that knows itself and knows its struggles and its mission, something a stranger to that particular community will not know.
Now this doesn't give us a licence to be inhospitable to visitors, but it does challenge the concept of over-working the need to be so welcoming that people feel "at home" straight away.
The article goes on to suggest that we view our Sunday gatherings in the context of being a family, and guests to a family event always come by invitation. In other words, there is always someone they have got to know outside the family context and who is there to help them navigate their way within the family.
If you have time, it's a post worth reading through and reflecting upon.