It seems that there's often not enough check up. Sometimes cops might even get the address wrong. Now, there is probably an argument to be made that no knock warrants are at times necessary. I can see the point for them when cops are going after genuinely dangerous criminals. But using them for drug busts is ridiculous. Someone in a meth lab isn't going to start a gun fight with cops for obvious reasons. Even people at a significant drug storage will most likely accept the situation when there's a SWAT team at the door.
And that raises the question whether these type of raids are happening because the police are worried about suspects getting rid of the drugs. And that sounds worrying. If the amount of drugs they're going after can easily be flushed down the toilet, then maybe they shouldn't be attacking people's homes like they're in a war zone.