I had a new character marry Quintus Navale today. Level 27, midway through main quest, done the Civil War questline for the Imperials and a few misc quests, mostly in Whiterun.
Lydia came, which made sense. She is my only housecarl and first follower.
Jarl Kraldar also came, which at first confused me but then I thought made sense. I had talked to him once, and it is because of me he is now Jarl of Winterhold so it was a nice way of showing his appreciation.
And Hemming Black-Briar came, which still confuses me. I never talked to him once. Possibly he is also grateful he is now the steward and son of the new Jarl of Riften thanks to me.
It's just...I decided to get married in Tavern Clothes and a circlet, so I have a horrible suspicion Hemming and had the following thought process when he saw me: "Ooh, I want a piece of that! I'd better follow her and strike up a conversation to find out who she is and what would be the best way to get her into my bed. Not going to the marketplace? The temple of Mara? The religious type then...#$@! She's getting married! Right now... I'd better sit down and pretend I was coming to the wedding or this could be awkward."