We had one cut through our traffic pattern about a year ago while one of my students was on a first solo.
Radio exchange:
Me: "Blimp passing through 5T6 traffic pattern, you up 122.8?"
Blimp: "Yeah, we've been making radio calls."
Me:"Well, the correct frequency is 122.725."
Blimp:"Sorry, our GPS is showing 122.8."
Me:"It changed over 2 years ago, so I'd say your GPS data base is out of date."
No biggy- it wasn't like the solo pilot could not work his way around it. I'm sure he'll never forget his first solo now as well.