During a job interview, the department chair and his wife showed me around town, and took me out for some meals. I don't know whether she was his chaperone, or she just wanted the free meals, courtesy of the math department's recruitment budget. She was quite skinny, didn't seem completely healthy, and looked like she needed the food.
At one restaurant, she picked up a spoon, reached over, dipped her spoon into my soup, and sipped it. I was happy for her to have a taste. I was less happy when she tried to do it again. I didn't want to catch whatever she had. I grabbed a clean spoon from the table and asked her to use it, rather than double dipping.
I did get an offer from that university. But you never know when a misstep with the silverware during the interview might cost you the job. I tell this story as an amusing anecdote about how you never know what will happen on an interview. I'm always surprised when my audience is shocked that the chair's wife would taste my soup without asking. Maybe that's cultural; I thought it was nice that she felt comfortable enough with me to drink from my soup bowl.
However, I don't think that state universities should pay for dinners for faculty spouses, or that the spouses should be involved in job interviews. It blurs the line between the personal and the professional. Mathematicians often have trouble drawing a clear line between their professional lives and their personal lives, and I've seen it lead to sexist behavior. It's important to remember to behave professionally with colleagues, even if the venue is a restaurant or someone's home.