My main takeaway from Lee v Lee’s Air Farming is that to determine whether something was a corporate act or an individual act, we should look to in what capacity the individual was acting when they undertook the act. Essentially, this means considering which “hat” an individual was wearing when they undertook the act.
Given this, the ability of X to use his corporation to avoid liability associated with a business outcome would depend on which “hat” he wore when he undertook that business action. Was he acting as an employee, or was he acting as the managing director or sole shareholder of the corporation? Whether X was acting in his role as an individual or in his role as a servant of the corporation may depend in part on whether he mentioned the corporation to those he was doing business with, but it seems to me that this would only be an ancillary concern.
The fact that X did not broadcast the existence of his corporation does not change the fact that it existed. As was driven home in Macaura, the separation of individual from corporation may work to an invididual’s detriment. There is no reason to try to jump through legal hoops to prevent an individual benefiting from distinct corporate personhood when the circumstances change in his or her favour.