In this case "came to" just means "attended". He came to class. He attended class. My parents came to my graduation. My parents attended my graduation. etc

You can say: The guests came TO the wedding. and The guests were AT the wedding.

Jazz and Peachey, thank you very much

In this case, "to" suggests some kind of transition, and it goes with certain verbs such as go, come, give, talk, and so on. The phrase "come at" exists, and it means "attack". ("Come at me, bro!!") "At" suggests a point or target, and goes with verbs such as look, laugh, throw and so on.

Hello, Reyn! The answer is: Hardly any guests came to Paula's wedding yesterday. We use 'to' when going to a destination.