Yes they are encrypted (I think). Being a season ticket holder I got excited, programmed them in and in the stadium was listening to my scanner through my phone and complete silence. That is unless my radio doesn't pick up the broadcast given I am in Benton County but I typically don't have an issue picking up Johnson County.
I have Google FI cell service by the way and don't have an issue with service on game days.
the UI made a weird (imo) decision to pay AT&T Wireless to manage a guest WiFi network but AT&T benefited the most from that relationship because they had very little spectrum in this market a decade ago. back then most of the cellular data traffic was backhauled over gigabit ethernet which was also terrible.
if your scanner has a discriminator tap feature you can confirm if there is anything over the air, my scanners (1080 and SDS100) can display an icon or play an audible chirp when encrypted data is being received but i have no idea how that is presented on any other equipment.
but i don't think big 10 network would want that radio system to extend much beyond Kinnick so i wouldn't be surprised if my house off Sycamore is too far to pick up 5-8W of DMR nevermind another county; the main county systems are trunked and have infrastructure to cover territory so it's no surprise Linn/Benton can listen to systems here but all that would do for Big 10 is give them problems so it wouldn't surprise me if it was intentionally designed for short distances. they want you watching the game on TV, not listening to or worse capturing and sharing embarrassing traffic. i don't know how robust encryption systems are for DMR but in my line of work we don't assume encryption is even functional and have to design for weak and broken.
edit: i'm not advocating for decrypting encrypted traffic, i'm pointing out that encryption isn't magic and like many things can be as effective as the implementation and planning for forward secrecy, etc. big 10 network takes that sort of thing very seriously and would likely design any solution in relation to the risk and remediation work required for a variety of attacks that are not only possible but are likely to happen. someone eavesdropping on coach comms would be a nightmare, so anything to minimize is likely in place. technology and hygiene/practices.