I believe there are two parts to that question, in terms of NDAs and subcontracting.
The first part is the term “ghost contracting”. I must admit that, in my 25 years of experience, it's not a term with which I am familiar. It's not a term I have heard. If what you are referring to is subcontracting, that practice, I believe, has been explained many times.
The Government of Canada deals with the contractor in question. The main contractor then has, following PSPC guidelines and rules, the ability to subcontract whoever they need to in order to get the work done. Those subcontractors and those engagements.... The Crown or government—in this case, CBSA—is not privy to that. The only one who would know that and could probably speak to your question is PSPC.