My kids' high school is the same. If the kid is in the AP class, they must take the test. We actually pay for the test at the beginning of the year. (It is not a public school though.) I think that's because the class is weighted more heavily, and they don't want kids taking it just for the weighted benefit.
They may SAY this, but they can't actually FORCE you to take an AP test. It costs money, and it's outside the normal scope of school. They're probably just hoping no one calls them on it.
Here's what our school does: You're required to take EITHER the AP test OR the teacher-made final exam. In reality, everyone chooses to take the AP test.
We actually didn't go to that many official Open Houses. I agree with your guidance counselor.

For most of the schools we visited, we would arrange a tour through the admissions office, often there was an information session first at the admissions office, then a campus tour with a student guide. After that we would normally go to the cafeteria to get a feel for the campus. We would look at the school newspaper, check out the flyers posted on bulletin boards (for activities, etc.).
We made a big checklist before we went to our first Open House, and it's kept us from forgetting a lot of little things. Because of our checklist, we've remembered to look for the laundry in the dorms, to pick up all campus newspapers, to note library and cafeteria hours, to check to see if there's a Baptist student group, etc.
The handbook now says if the student does not take the AP exam, they will lose the AP designation and weighting and will be referred to the principal for disciplinary action.
They may SAY that, but in reality, there's not much the school could actually do. And that's fair.
I've told this story before, but here it is again: When I was a junior in high school I signed up for several AP courses to be taken my senior year. By the time I was close to graduation -- when I would've taken the tests -- I'd decided on my college, and I knew they weren't going to give me credit . . . not even if I made a perfect score. So I didn't waste time or money (and those tests aren't cheap) taking tests that would've gained no advantage for me.
If you were the principal, would you really punish me for that decision?
From our DS18's experience, I am going to make sure the kids visit schools on a weekend as well. We asked about weekend life when we toured and our tour guide said that lots of kids stay on campus and there was a lot to do. We didn't take into consideration that she was a senior and we were looking for information about freshmen. DS's dorm turns into a ghost town every weekend and he is probably not going back there next year because of that. Most of his friends are not going back either.
My college was like that, and I loved it! During the week, the place was packed and it was fun. Thursday nights -- late Thursday nights -- everyone went out to the clubs. And on the weekend something like 2/3 of everyone went home. So the dorms were quiet during the day, and those of us who always stayed hung out together on the weekend. My roommate always went home, so I had a private room every weekend; I think that's why we stayed together so long when other roommate pairs dissolved. The people who stayed became my close friends -- THAT was what made the difference. It was kind of like going to two schools -- one large, one small.
I think I've mentioned this before, but, with the talk of unhappy kids transferring, it should be said again... When you're looking at schools, look at stats on how many students return for their sophomore (and if you can get it, junior) year. My middle son transferred from his original school -- looking at these figures, it shouldn't have been a surprise that he did.
To be fair, kids don't always transfer after freshman year because they're
unhappy.
Some transfer because they had a nice fat scholarship freshman year, and it doesn't renew -- all too many people don't consider that, and they figure that further financing will just work out. After all, didn't they get the first scholarship? But all too often, it doesn't happen that way, and at the end of the freshman year they're scrambling to choose something they can afford.
Or they don't do too well academically. Maybe because they were too involved in having fun, and Mom and Dad say, "You're coming home."
I think also that if you have a school that has 20 valedictorians that either there is a lot of grade inflation going on or the school isn't challenging the kids enough
Or the school doesn't weight GPAs. Consider this:
My daughter's high school calculates BOTH weighted and unweighted GPA and both appear on the transcript. She has made one B in high school . . . so her unweighted GPA makes her #2 in her class and her weighted GPA makes her #26. So with the unweighted GPA 25 people in her class have made straight As thoughout high school -- a feat, yes, but not an impossible feat that means they weren't challenged. And those 25 are tied for #1. I don't know how many people are tied for #2 along with her.
The weighted GPA is more fair because it gives more credit to those who've taken more AP classes. Some of those kids in the #1 position are in the self-contained special ed class. I don't begrudge them their As -- they worked hard for them -- and they'll not be competing with our honors/AP students for college spots, but an A in a self-contained special ed class isn't equivalent to an A in Advanced Junior English or AP Chemistry. When you look at the weighted GPAs, those kids still look good on paper, but they aren't in the top 10% of the class (because they're all general-level classes, which count less than honors or AP).
While there is nothing "wrong" with it, a college that receives 5 SATs from you will wonder why you had to keep taking it so many times.
And then there's the money. I was SHOCKED at what it cost to take the SAT.