They may not track how many tours you did or if you attended when USC visits a school and gives a presentation by AO’s, but if an applicant makes an impression at one of those, that is a different story. That is not demonstrated interest of the tracking kind, that is a student successfully demonstrating their interest. Of course these things are taken into consideration. If an AO, professor, or person giving a presentation at an admit event, or any person of influence in the admissions process has met or been in contact with someone and is impressed by whatever form of interaction with them, they don’t just ignore that or separate from it’s influence - they are gonna put a little gold star next to the name, a note, or provide input to those making the decision. “Hey I met this/got an email from this kid today who was incredible…he told me…” They are an admissions team that goes beyond the admissions team. If it comes to the total unknown who has not engaged with anything USC except for google, or one that through whatever form of contact or inquiries they believe will be an engaging member of the USC community, their gonna pick the latter everytime.
So this isn’t a thing that can be seen as “unfair,” it’s just common sense. Kids don’t have to fly in and do a tour. No one has an advantage that someone else can’t get too. They should not reach out with mindless chatter whether email or live, that will always backfire. Kids aren’t taught how to do this, they got “it” or they don’t. There are other ways besides personal contact to make an impression (both good and bad), particularly in the essays which is another place to craft a story that demonstrates interest. In the admissions processes at every college, it is not always black and white. Interpreting “rules” strictly isn’t helpful, rather, just think about how humans interact and make decisions, and it’s easy to see the difference between tracking demonstrated interest and a student demontrating interest.