> There may have been others, but this is how I remember it.

Uh, yeah, DC949 ran Open Capture The Flag (OCTF) at Defcon from 2005 through at least 2010[0].

We later ran the original Barcode Shmarcode[1] contest during Snowpocalypse at Shmoocon so I know the Ghost in the Shellcode team was at least somewhat aware of DC949.

[0] https://www.youtube.com/watch?v=9Gs2Ja6Gt4Q - DEFCON 18: oCTF: 5 years in 50 minutes 1/4 (2010)

[1] https://www.shmoocon.org/barcode-shmarcode/ - Shmoocon: Barcode Shmarcode