Now we come to my tentative suggestion. There is no fact of the matter as to where the BOP lies in any dialectical context, legal, philosophical or any other: it is a matter of decision and agreement upon what has been conventionally decided. In chess, for example, the rules had to be decided and the players have to agree to accept them. No one thinks that these rules are inscribed in rerum natura. The same goes for BOP and DP. It had to be decided that in court room discourse and dialectic the accused enjoys the DP and the accuser(s) the BOP.
In philosophical discourse, however, there are no procedural rules regarding DP and BOP that we will all agree on.
This is my view, at least for burden of proof*. Some of the posts in which I've discussed this:
The Fiction of Burden of Proof
On Van Inwagen on Burden of Proof
* For BOP only, however. Unlike Vallicella, I think defeasible presumption (DP) and burden of proof (BOP) come apart. I think defeasible presumption is merely one of the things it is reasonable to take into account in negotiating burden of proof.