This is a good example of how sometimes noble intentions can just run amok.
The idea of a CRB check was noble. Let's protect the kids, vulnerable adults and general undesirables away from trusted jobs.
However, over the years the govt have allowed political correctness to run amok, to the point where even plumbers get themselves CRB checked.
I remember reading about a case where a child was regularly taken to school by taxi. No problems, the taxi driver was CRB checked. However, one day the child's mother joined them. Oh no....she wasn't CRB checked. Not allowed, sorry! Bonkers!
If the CRB check morphed out of control then the V&B system was a disaster in the making. Can you imagine the results of a system where unproven allegations are used to make decisions. Oh we had the "assurances" that it would be fair.
Can you imagine the impact on teachers? One allegation and their job was effectively over. Doesn't matter how bonkers the claim was. It would have been held on record and taken into consideration. Now if you were a headmaster, would you employ someone with allegations of sexual abuse from a child?
Anyway, coming back to OP's point. I sincerely hope you told them to grow up and not to bother to come if that's how stupid they are being.