I say think about it from their perspective.
They don't want to be rude to you, and want you to have a good interview experience, even if they know you aren't going to get in.
Later on you'll get in somewhere, and always hold a grudge against their school, telling all your collagues and students (I remembered when I interviewed at ....., and they said this, and did this, and made me feel like crap".
I think interviewers telling applicants "see you in the fall", or "You're in" is really irresponsible. They might not be able to guarentee that, and really cause someone trouble. If I was told that, and didn't get in, I'd think that some transcript was wrong, or someone lost some LOR, I'd start freaking out.
I liken this experience to a first date. You guys talk a bit and get to know each other, and maybe you'd be perfect for each other, getting married and such. But if one of you says something you didn't mean, or says something silly, usually won't be a second date.
Its not a big deal though, as there are a lot more med school in the sea! 🙂