If active model declares a BS attack & it outside both the targets ZoC & LoF does the target get to declare an ARO?
Yes. It's called ARM roll. Serious answer... If it is a normal BS Attack, no ARO. If it is a Template placed on the model, Dodge -3 (due to not having LoF on the attacking model)
The active model gets to make normal rolls for their attack in this case, and the reactive model has to just stand there and hope for the best. The reactive model does meet the requirements for the Alert skill, however, letting them and friendly models in their ZoC change their facing during the Conclusion step of the order.
