I know 40 years ago the NORKs would run their jets as fast as possible towards the border in attack fassion then veer off at the last moment prior to crossing th 38th.
We’d send up fighters to challenge.
Happen sometimes several times a day.
Seoul is about 3 minutes flying time from the border. Folks were not casual about this.
I heard that, too. Now we do not have to worry about it. Their planes are turning into rust buckets. However, they have the new toys more dangerous than those planes.