"During taxi, the momentary use of idle reverse thrust may be needed on slippery surfaces for airplane control. The use of reverse thrust above reverse idle is not recommended due to the possibility of foreign object damage and engine surge. Consider having the airplane towed rather than relying on the extended use of reverse thrust for airplane control."
Sempre dal FCTM. Il fatto che Boeing non spieghi neanche come eseguire questa manovra secondo me la dice lunga: della serie "se proprio devi, falla pure, ma io non c'entro niente".