That would be way to hard to track. You would have to family share everyone that was in the raid and its already a big problem to keep track of whether a raid is active or not.
You cannot gain the full advantage of using 2 accounts (unless your Anna) as you simply can't pay attention to both at the same time.
Each user has there own nlr timer and each is eligible for warnings. Why put restrictions on something so minor and make the life of admins even harder during raids? Could you imagine the confusion.