AP Invoice Approval BPM - Use of priority to skip stage/reject any transactions that would error

Summary:

We want to create a rule that will trigger in case no result is found in the ruleset, to make management of the rules easier and prevent issues that were introduced in a recent update.

Content (required):

As a workaround for an issue (described at bottom of question), we want to implement a new stage with autoreject rules for any invoice that's submitted to the workflow, but which will never trigger an approval rule (thus erroring out).

I figured we could use the priority for this, setting all auto reject rules to priority = medium and then creating a rule with operand 1=1, priority lowest, that will ignore any invoices that should pass the stage.