Discard the validator registrations from slashed validators?

According to the current spec, builder software can accept registrations from validators who are currently active but also slashed.

Given that slashed proposers cannot produce valid blocks, we could tighten the spec to disallow this set of possible registrations.

It is a bit of an edge case but does reduce the possible load on builder software so I wanted to open this issue to see if there is any interest to modify the spec here.

Start by reading the current builder specification section governing validator registrations and the handling of slashed validators. Confirm how the spec defines active validators and whether builder software must accept these registrations. Done means the project reaches a decision and, if accepted, the specification states the revised rule consistently.

Written by the indexing model from the issue text.