There is no binding that occurs - period.
Any database needs a workgroup to be associated with it.
The association is not 'real' in any sense, or connected in any fashion, other than you simply specifying the file when opening a connection. Perhaps this is just semantics. Read the help file, or better yet, the security faq. You are making incorrect assumptions about how to apply security, then claiming the product is flawed because it doesn't work in the expected fashion. If anyone knows how to get around this problem, I'd appreciate your input.