U16 Soccer: Heavy Contact After an Offside Whistle—Yellow for Reckless or Red for Serious Foul Play?

A U16 soccer referee describes a play where an attacker is whistled offside, stops, and is then hit hard by a defender less than a second later. The on-field decision was a yellow card for a reckless challenge with an indirect free kick for offside, but another referee argued it should be a red for Serious Foul Play—sparking a rules-and-officiating debate about contact after the whistle.