I think it's up to the universities. But they should not be able to stipulate that you need to put them as a firm.
If, for whatever reason, they decide you're a really good fit for their course and would sail through but don't need the pressure, then they can give an unconditional. However, to insist they be your firm just shows they are after numbers, and don't really care how you do. Of course, since employers don't really care how you do, that's a bit of a moot point at present, but the system isn't going to get fixed if universities themselves contribute to breaking it.