As a guy, I would not be okay with this. Trusted or not, sending your gf into a drinking social event where the expectation is to pair off and get "better acquainted" with one another is inviting disaster, especially in an environment where, in this case, the other same-gender people are not going to be looking out for your best interest. They're all going to be busy trying to get hooked up themselves, or as shown, are willing to use you for their gain. There's also not really any kind of filter for the type of people invited, besides "not an open serial killer." This is a great way to get roofied too. Also, too many NTR/hentais start off this way.
But because the MC is a guy, this becomes marginally more okay? Call me possessive and triggered, but even as a girl, the only way I would allow this to fly if I don't think my other's friends are going to look out for him/her, is if I get to pick my bf/gf up at end, and my bf/gf better not drop off contact for hours.