It's pretty much required, for obvious reasons, for CPS to put mitigations in place for whatever they might be investigating. Mitigations often feel like punishments, for sure, with the key difference that they are only until the investigation is resolved.

Is it though? If that’s necessary why isn’t it necessary to lock someone up while you investigate whether he might be involved in drug dealing, just in case he might be guilty and destroy the evidence?

Wait... I think you've got cause & effect backwards here.

The police arrested the mom, not CPS. There was no interaction between the family and CPS prior to the arrest. The arrest is what brings CPS in to the picture. Just by virtue of arresting a parent, CPS should to get involved, because arresting the parent potentially puts the kids at risk... and then you double down on that because they've been arrested for endangering the kids. CPS then needs to figure out the lay of the land, so that they can establish that the kids are NOT at risk and they can step out of the picture.

What I’m objecting to is the imposition of the “no unsupervised time with your children” rule, which, to my mind, is a punishment just as much as a precaution.

> What I’m objecting to is the imposition of the “no unsupervised time with your children” rule, which, to my mind, is a punishment just as much as a precaution.

Which is another way of saying that it is just as much a precaution as it is a punishment.

CPS responsibilities are to the children and their safety. The police & courts deal with the parents, collect any evidence, mete out any punishment, etc.

Well then that brings me back to the other point. We could do this with far more suspected crimes. Just to be safe.

We do do this for other crimes.

Again, CPS isn't focused on the crime.