Either 280ft is longer than whatever type of football field they're thinking of, or it's not. No understanding of football needed for that.
You haven't said what part of it you think is wrong - though I do believe that both American Football and Association Football (aka "soccer", or "real football" :P) do both play on pitches a bit longer than 280ft.
You haven't said what part of it you think is wrong - though I do believe that both American Football and Association Football (aka "soccer", or "real football" :P) do both play on pitches a bit longer than 280ft.