why does someone who rsvp'd no to a wedding suddenly email and want to know who went to the wedding and how many came to the wedding?

Sounds like they are being a bit nosey. Or they are trying to confirm what someone else has told them. It would be perfectly fine to ask why they want or need to know.

They're rude.

Could just be their way of making conversation. If you invited them, they have some connection to you, and may just be curious about the ceremony and reception.

How are strangers on the internet supposed to know? Ask the person who emailed you with those questions.

Nosiness.

Just plain nosy.

And? You're not obligated to answer them, you know.

You have several options of how to reply:

- "We wound up having # people in attendance."

- "Why do you want to know?"

- "That's none of your business."

- or just ignore the question, especially since it's an email

The person may just be trying to be friendly, or maybe they're very nosy. Either way, you aren't obligated to respond.

Perhaps they want to know what they missed out on.

You don't need to tell them if you don't want to.

Ask them why they are now interested in an occasion they weren't interested in joining before,

That's just downright rude to ask.

DOn't get involved in feeding a rumor mill. Simply decline to answer.