Catch the bad guys while they're still in bed/hung over/etc.
In other words, they are intentionally forcing encounters at times when the target party is least likely to be able to make rational decisions, or at times when someone might reasonably suspect a person at the door could be dangerous and thus arm themselves before answering.
This is Branch Davidian enforcement ethics. Unless the person simply never leaves the house, they are picking the most dangerouns possible times to serve warrants. That’s a terrible decision for everyone involved.