Yes, but there is still disruption as BA have to make the contingencies.
But, if no-one actually strikes - there is no question of 90 notice, or sackings or legal comeback.
Call a strike - but only the would-be strikers KNOW that it isn't.
It's not illegal to turn-up for work when a strike is called.
Happened quite a lot during the last rounds I recall. Ironic eh?