What is Throw A Red Flag?
1.
To challenge the ruling on the field, i.e. call someone out on something that you believe is bullshit.
Derived from the NFL practice of coaches throwing a red flag to request further review of a play and give the network a chance to show 2 more minutes of commercials.
person 1 - My bad on not helping you out, I was working all day yesterday...
person 2 - I'll throw a red flag on that, you told me three days ago that you don't work weekends...
person 1 - Well, yea but...nevermind...
See