HAHAHA - I get what you are saying, but from what I understand colleges are using the same company that the NFL uses for the tech.
Listening to a radio show here in B1G country (where signal and sign stealing is some what of a hot button issue), it seems that each team will have a set of digital band frequencies and the operators will roll through those bands almost continuously making it nearly impossible to break into and listen to a communication or jam that signal.
The only way we as fans are privy to any of the NFL mic'd up stuff is because the league grants permission for the team and controllers to stop for a few seconds at a set frequency.
The lengths that have been gone through to keep people from breaking into communications and talking or listening are mind boggling.
Also, there will still be side line signaling as only one or two players on the field will be equipped for in helmet communication.
The signal will still come in from the sideline to the rest of the team.
That's a huge part of our offense if you notice as the WRs are jogging towards the side line to get set for the play they are getting the signal from the sideline...they rarely get the formation from the QB.
That way when they get to formation, they are already set and the ball can be snapped almost immediately.
Now where this in-helmet communication may hurt this offense is a signal is sent from the sideline, everyone gets that signal and sets, coach send an audible across the helmet, the QB now has to audible and if the new signal is not close to the original in terms of set, there has to be movement (which is waste) and that costs time.
Sorry for rambling - I've been reading up on how this works since they used it in the bowl games last season.
Indiana, I haven't read up on the NFL and NCAA efforts in this field as you have, but it is possible what you thought of as "operators rolling through frequencies" is actually automated. And happens on the order of a frequency change every less-than-a-millisecond. Like, they're going through 1,000 or more frequency changes every second.
That's called frequency-hopping, and has been part of radio encryption technology since the 1970s. We had it in the US Army in the early 80s when I was on my very first tour.
Each team would have their own unique, randomly-generated encryption key (not really a physical key, more like a super-long password on a closely guarded memory stick), which sets up an algorithm--a mathematical formula--for which frequency to go to next, then next, then next, then next, and also keeps everyone using that key on the same 'heartbeat' for the shifts.
Some dude in charge of communications for the team generates a random "key" before the game, then goes from radio to radio physically copying the key into each team radio, including the ones in the players' helmets.*
As long as that dude keeps his mitts tight on his key generator, and all the team radios stay in friendly hands, there's no way anyone else can listen in. Mathematically impossible.
And it is entirely possible both teams are using the same band of frequencies. If I'm randomly hopping among them using one encryption key, and you're randomly hopping them using another, we will never even notice each other.
The only way to jam a frequency-hopping network is to blast the jamming signal on ALL those thousands of frequencies they're using, or at least the majority of them. So much harder to jam, though not impossible.
Really fascinating stuff, and entirely unbreakable unless you can steal or talk a turncoat into giving you the other team's encryption key.
Go Vols!
* Edit and possible correction: it has been decades since I last used FH radio encryption--it is entirely possible they figured out secure ways to pass the key from radio to radio without even needing a guy walking around with a memory stick. Showing my age, heh.