Is flag guarding illegal in flag football?
Yes. 5 yards and a loss of down.
Flag guarding is the ball carrier trying to stop a flag pull by covering a flag with a hand, arm, leg or the ball, or waving a hand down in front of a flag before the pull.
Pushing a hand or the ball out toward a defender to keep them away from the flags counts too. It’s a foul even when there’s no contact. Jumping and diving to keep the flags away are treated as flag guarding as well.
IFAF Flag Football Rules 2023, R 2-12-2, R 9-2-2-c
Flag guarding: 5 yards from the spot of the foul, plus loss of down (signal S52).

NFL FLAG and local leagues can differ. Check the rulebook your league plays.
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