DD says heels. Parent thinks tour is too much walking and 8th grader in heels at interview is too grown-up. 8th DD says heels best. Not sure. Maybe parent is out of touch.
My kids wore sports shoes when they interviewed for HS. It worked as both were admitted and could comfortable walk around the campus. Our D didn’t even OWN any heels in 8th grade and her back and feet are grateful!
Flat shoes. They don’t have to be dowdy to be practical. The tour will involve walking. Probably a lot.
Flat/comfortable shoes, both for kid and parent. It’s a lot of walking, and she will be miserable by the end of it if she is in heels. She’ll probably be the only one in heels, which will add to her discomfort.
Definitely flats or a low heel. There is more walking than sitting.
Flats for sure. Heels will most likely seem to formal and you don’t want to be uncomfortable, because a large percentage of your campus visit is walking. If your daughter is still insistent on heels, maybe meet half way at a very low wedge?
Flats for sure. In fact, you won’t see many students in heels either.
Flats for certain. For me, personally, I travel in sneakers and carry dress flats. I have ruined my feet and can’t wear hels at all anymore. I think high heels for an 8th grader is not appropriate for an interview.
I agree that kids still in middle school should wear flats and wear clothes that are clean and comfortable. You want to look good and avoid wardrobe malfunctions. From personal experience, wearing flats or other shoes that are extremely, very, totally comfortable is what you go for because hobbling along with blisters and …is beyond painful and not a good look.
Oops uncomfortable. Wear shoes that ware tried and true for walking rather than a new or untried pair for extensive walking.
I will tell you first hand, FLATS!
I made the mistake of heels and after the first school, I stopped and bought a pair for the next day
Flats - so much walking. You want to be comfortable!
Let her wear whatever she wants rather than make it a battle. I can’t think of a better “natural consequence” for insisting on heels than sore feet… She’ll wear flats for all subsequent tours 
Agree with @CaliMex – smile and nod, but insist on bringing a pair of flats along " just in case". Arrive early, walk around a bit, see what the students are wearing, and she’ll likely decide to go for the appropriate flats. ( of course, this advice is coming to you from the mom who dropped kid off at tour/interview with seconds to spare, parked the car and followed inside, only to realize that I’d forgotten to change out of the slippers I’d worn to drive in. Fuzzy blue slippers, in fact. ) 8-|
DD started wearing heels regularly since 9th grade. She thinks it helps her socially by compensating her height. It wouldn’t have been bad if she started it a year earlier and went to her interviews on heels if she wanted to.
I also agree with @CaliMex , and stow a spare of flats in case she changes her mind. DD wore flat boots actually, because she hates most other kinds of flats, and those were perfect. Appropriate yet cool, comfortable, and perfect for New England weather.
Wear shoes that are made for walking.
I just went on a university orientation for incoming students with my younger daughter, and noticed one other person there with flip-flops. Not a good plan given the amount of walking that we did. High heels would be even worse.
Wear the ballet flats with the CC’s on them!! ;).
Personally, I say flats. But, if you decide to let her be the decision maker, then under no circumstances should you bring flats “just in case”. Learning to live with choices is an important part of growing up.
My daughter wore converse and got accepted to 4/5 schools!