The US Constitution says:
no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
The Texas Constitution says:
no warrant to search any place, or to seize any person or thing, shall issue without describing them as near as may be, nor without probable cause, supported by oath or affirmation.
A warrant based on "evidence" from someone not known to the person swearing the Oath or making the affirmation, is no different than not having an sworn affidavit at all. "Somebody said" is not evidence, nor probable cause.
If the LE hurried over to my house at O Dark thirty, and were not real polite about serving that warrant, they might not like the reception they'd get, and neither would I, I'm sure.
They couldn't have served the search warrant during normal daylight hours? Was there *imminent* danger, as opposed to "potential" danger. IOW, could it have waited until morning? I think the answer is obvious.
It also shows no due diligence that they did not even check phone records to see where the call originated.
That said.. the kids were taken because of what CPS saw after they entered.
Be that as it may, if the warrant is later deemed to be "bad", then all the evidence collected thereafter will probably be deemed fruit of the poisoned vine, and not admissible. So if there were crimes committed, the perpetrators will either never be charged, or they'll skate because of that bad warrant.
Now if there is imminent danger to person(s) or property or an LEO observes a crime in progress, no warrant is needed. But it needs to be clearly imminent danger, or a crime in progress, not some "out there" accusation from a voice on the phone.
As for me...I've seen injured children. My take is...do your (CPS) job and do it right. If you think the kids are in immediate danger do something. If you are just on a power trip or remove them because you are afraid of future what ifs then be prepared to get sued , big time by the parents.
Time will tell if CPS called it right. Right now they are looking like they have a stronger case than the "parents" though. We'll see.