Earlier this week I was at a friend's wedding, and I had to leave shortly after the Chupah. That made me wonder: with regards to saying all 7 of the blessings at a "Sheva Brachos" meal, we require a Panim Chadashos ('new face', someone who hasn't partaken in the wedding festivities with the new couple yet). However, how 'new' must the person be?
- If someone was at the Chupah, but no other part of the wedding (specifically that part, as Sheva Brachos are said under the Chupah too).
- Only there for the meal. By a Siyum I know that (at least some opinions) hold that being at the meal alone is enough to be considered 'part of the Siyum'.
- You happen to meet the couple somewhere, something as simple as walking down the street. You wish them Mazal Tov (or not, maybe that would affect the rule) and keep walking along.