If, prior to the delivery of the sixth stone of an end, a delivered stone causes, either directly or indirectly, an opposition stone in the Free Guard Zone (FGZ) which is touching the centre line to be moved to an off-centre line position, the non-offending team has the option to:

(i) remove the delivered stone from play, and replace all stones that were displaced to their positions prior to the violation taking place; or
(ii) leave all stones where they came to rest.