Question about adding a reference in ASP. net2.0

I have been using. NET 2.0 for a while. I have never found any difference between adding a reference and the previous 1.0. Today I suddenly found a problem. For example, there are three projects in a solution: Bll (business logic layer), Dal (data layer), and Web (Wet Application Program). The trust relationship is that The bll layer references the Dal layer, while the web application references The bll layer. In the previous 1. in Version X, I want to reference the BLL layer in a web application. I only need to add a method to reference this project. In a web application, I can only access the methods of The bll layer and cannot access the Dal layer, the same is true when the BLL layer references Dal, but I found it different in 2.0. I only added a reference to the BLL project in the Web application, but the Dal project will also be added automatically, and I can directly access the BLL project during the web application. I tried this for multiple times without adding references. I just need to copy a DLL file to the bin folder and then access it directly. I don't know if it can be set, or the 2.0 mechanism is like this. I think this mechanism is not good. Originally, my web application can only access the business layer, but now it can access the data layer directly.
?????? Confused