The hashes can not have collisions anymore, because modern forensics hash with both md5 and sha512, and both hashes must be together for use in any legal case. The odds of both of them having a collision is big enough to flat out say it's not going to happen.

But even if there was an md5 hash collision back when md5 was the only one hash use, it still doesn't matter because upon viewing the image that matched, if it's not csam, it doesn't matter. Having said that, the chance of dozens of images matching hashes known to be associated to csam is also so unlikely as to be unthinkable. Where there is smoke, there is fire.

And further, a hash alone is meaningless, since in court there must be a presentation of evidence. If the image that set off the csam alarm by hash collision is say, an automobile, there is no case to be had. So all this talk about hash issues is absolutely moot.

Source: I have worked as an expert witness and presented for cases involving csam (back when we called it Child Pornography, because the CSAM moniker hadn't come about yet), so the requirements are well known to me.

Having said all that, I am an EFF member, and I prefer cryptography to work, and spying on users to be illegal.