The residency pre-interview dinner is different than a pre job interview dinner with one or two other couples, where they are trying to sell you and your spouse on a job. Most of the time the residents are coming directly from work, without their SOs. And at places where the resident vote matters, you are very much being actively interviewed at that pre-interview dinner, and your goal is to work the room, not have a pleasant couples dinner. Totally different animal. And in terms of your spouse charming people, I've seen that backfire frequently. Inevitably one applicant will get outshined by his spouse, and the residents will come away saying "wish we could hire the spouse instead of the applicant".