I have worked in Public Works and in a number of departments, on issues involving contracts that are subject to NAFTA.
The process does include an evaluation stage for bidders. Individuals who go through all the steps may not have realized that their rights were violated. The process proceeds, and they trust in the system. It is transparent, and there are meetings held. When the bidder is chosen, one of the parties competing may say that they do not understand the decision. In that case, they may file a complaint with the tribunal.