Keep the Groom Away from the Future In-Laws

Our guest list currently stands at 330 people. Which is a lot. It's quite a bit bigger than I had initially anticipated. The majority of the list comes from my side of the family, which includes immediate family (of course); aunts, uncles, and cousins (we're close on my side, so of course), and my dad's cousins and their children, which includes many people that I haven't seen in years (or ever, if I think about it).

The conflict arises here:

When I pictured my wedding, I imagined that it would be a large affair, but not 330 people (or even 275 with the "only ~80% of the invited guests will show" rule). Without having sent any invitations out, I'm already hearing (second party) that people are coming to the wedding. The wedding is turning into a family reunion, which is, on one side great - who doesn't like a family reunion?, but on the other, I'm not able to invite some of my friends, a difficulty everyone faces when planning a wedding, but really just not a fun situation.

Now to the title of the post. On the recent family vacation, my fiance, my dad, and I were relaxing in the hot tub, when the topic of wedding showers came up. "Oh, well, I'm sure your mother will have a shower with her tennis friends."

"I don't know, I think traditional etiquette says that a shower should only include people who have been invited to the wedding." (I am not stating this as fact, I'm actually not sure, but I think I read it somewhere.

"Well, I'm sure some of your mother's friends are going to be invited to the wedding."

At this point, I told him that I wasn't sure, because the guest list was already at 330, when my fiance joins in:

"I'm pretty sure that a lot of my family won't be able to make the trip to the wedding, so we might have that many people."

"OK, so we can invite more people, since they probably won't come."

Fantastic.