It's reasonable, in the same way it's reasonable to have people sign a receipt saying they got the package, or that its reasonable to have people sign a ticket (saying I am not admitting guilt by signing this, only that I was in fact presented with this paper). If I refuse to do any of those things there is an escalation (in the last case it's arrest and the impounding of the car!).

CPS does need to document that they took certain steps with the parent, or it doesn't count in court... instead they get in trouble for not being able to prove the parent was there, and discussed the welfare of the child.