Part of the problem comes from the routine, too many cops were getting killed because of it. You walk up to serve a warrant for a rinky dink charge and someones meeting you at the door with a rifle.
I had a Garand pointed at me over a contempt charge (originally a dog at large ticket). Finally got the homeowner to use common sense and come down and just pay the $30 fine.
That kind of attitude, from both sides of the badge is getting people killed.
As to no knock raids, unless there are extreme mitigating circumstances, weapons or evidence destruction, they shouldn’t be used.
Swat gets used more and more lately because its a training issue. Its cheaper and easier to use the Swat team to serve warrants than to train and retrain the entire department to a respectable level. Your average traffic cop is more a hazard during a warrant service than many armed dopers, and with department budgets getting cut hand over fist, its hard enough just getting in state required training let alone specialized training.
Our local SO has had its budget cut so far by the county commissioners, they are 7 deputies down and can’t hire more, they can’t afford to send people to required training, no vacations, etc. Deputies are sent from one side of the county to the other to cover calls because there is no one available on that side.