When I got married, right after my semester in grad school, I didn’t bother inviting my non-Orthodox classmates. We weren’t really friends, they didn’t seem to mind, and it my father objected. Strongly.
Recently, a frumguy in my class got married, but he did invite everyone who wished to come. Only one non-Orthodox girl showed, and she’s had experience with Orthodox functions and blended seamlessly in with the frummies. And I mean seamlessly. She knew exactly what to wear, how to act, what to say. Impeccably.
The last time she attended an Orthodox similarly deported, she told me, someone had asked what she was looking for. A hook-up, she called it, in the Orthodox style.
I find it rather amusing that the non-Jew navigates the being-seen-at-a-wedding shidduch must better than I ever did.
My father should not have worried.