Ceremony is at 3, but we'll be serving welcome drinks (champagne and non-alcoholic beverages) prior to the ceremony. It has been ages since I've been to a wedding myself. Do people nautrally show up far enough ahead of time that they'll be able to have a drink?
Our invitations are informal and lighthearted so I could put in a sweet little fyi-ish note that they can come a little early for a drink before the wedding.
Or is say a 2:30 arrival for a 3 PM ceremony a forgone conclusion?