My DH and I excluded everyone - we got married, just us two with random courthouse witnesses, on our lunch hour. It was wonderful and no one had a problem with it (or told me they had a problem).

My DS is newly engaged. DH has asked him, if he has a wedding, to exclude several of his siblings and their families. There have been issues with their father's estate and unsupported accusations and hard feelings resulted. The siblings will probably not care, the relationship is that far gone.