Interesting question, I hadn't heard this one before. So by and large, you have a lot more freedoms in college. I remember in high school we had a "dress code" of things we could not wear in school, no hats were allowed, no chewing gum, no laptops in class (this has since changed), no cellphones visible, and a few other rules that I hated at the time. The thing with college is that all of those restrictions largely go away. Now if you go to a religiously affiliated university or a university that has an honor code, you may find yourself back in a school with restrictions. My university didn't have those restrictions and people were free to wear what they wanted (sandals included). I have seen people in my classes wearing sandals all the time during the summer, though there were definitely some people that needed to practice better foot hygiene.
There were some professors who didn't allow laptops in class and would ask you to put away your cellphone if seen, but I have never been in a class where the professor had a "no sandal" rule. If you are in a science class with a lab, then you are probably not going to be allowed to wear sandals for safety reasons. I had some engineering friends who couldn't wear sandals, had to have their hair up, and had to wear safety glasses on during their lab classes for safety reasons as well. Other than the obvious, I think you will be able to wear sandals everyday to your heart's content. Just be sure to take good care of your feet as I have seen some people with gross feet walk into class.
I hope this helps and I wish you the best of luck in college!!