I don't get it

Apparently, there is a new practice called "SWATting", where someone sends a note to the police alleging an urgent criminal situation whereby a "dynamic entry" will be undertaken.  OK, I understand the motivation, I understand how it works, but one thing I do not understand:  without clear identification of the person making the allegations, why are the police acting on this with a "dynamic entry"? 

The reason I ask is simple; one of the key issues homeschoolers like my family deal with is unwarranted investigations, and one of the things the HSLDA consistently does for its members is to remind over-eager social workers and policemen that they do not have warrant for an investigation on the basis of an anonymous allegation.  Federal law requires peace officers and social workers to be trained in the 4th Amendment.  So why is this working?

The only answer I've got is that many peace officers are still not taking the 4th Amendment seriously, and it's about time they did.

H/T Mr. D and others