Are parents helping each other with child care breaking the law?
Two mothers from Buckinghamshire, who worked together as policewomen, have found themselves at the centre of a dispute over childcare rules - because they were babysitting each others' children.
Why did Ofsted inspectors knock on their door?
The claim against the arrangement was that the two mothers were looking after the children for a "reward" - in this case, helping each other with childcare, which they say helped them return to work.
The Childcare Act 2006 talks about "reward" without making a distinction between financial payment and other incentives, such as a swap between parents.
Where there is such an arrangement, the person caring for children in their home (rather than the child's home) might then have to be registered and inspected by England's education watchdog Ofsted. Failure to comply could lead to a fine up to £5,000.
Does everyone who looks after each others' children need to be registered?
There are exemptions. As well as parents and step-parents, relatives do not have to be registered. Relatives are defined as "grandparent, aunt, uncle, brother or sister, whether of the full blood or half blood or by marriage or civil partnership".
What about friends helping each other with child care?
The regulations depend on where and for how long children stay with another adult.
If the child is not looked after in their own home - for instance, if they are brought back to another parent's house after school - and they spend more than two hours, then the rules on childcare apply.
To add another layer of complexity, there is no compulsory registration when childcare takes place between 6pm and 2am.
Frequency is also a factor - with exemptions for 14 days or fewer in any year, if as Ofsted says, "you tell us in writing at least 14 days before you start to provide care".
In theory at least - and as the two policewomen in Buckinghamshire found - this would mean such a regular, informal, daytime arrangement between friends had to be regulated and inspected.
There is no clear distinction between informal arrangements like this, and those people who care for children for a living.
Under the requirements for such childcaring, there are long lists of the facilities, supervision and safety checks that have to be inspected.
What about babysitters? Do they need to be registered with Ofsted?
The Childcare Act makes no reference to babysitting, not distinguishing this from other forms of commercial or informal child care. Presumably this means that babysitting becomes a form of looking after children for reward.
But there is an exemption for care between 6pm and 2am - and for care in the child's home - which could mean that in most cases babysitters would not need to be registered.
If the child is looked after at the babysitter's home for more than two hours, outside these hours, on more than 14 occasions per year, then they would have to be registered, as this would be "provision on domestic premises for reward".
But if a couple of parents agree to share getting children from school...?
Such play-date arrangements, with friends going back to each others' houses after school, offering a "reward" for both families, taking place in day time and on a regular basis, would be illegal under Ofsted's interpretation of the law.
Ofsted would not be likely or able to pursue such arrangements, but nevertheless, as the two policewomen discovered, that is what the law sets out.
Is this throughout the UK?
Ofsted only operates in England - so this controversy applies in England rather than elsewhere in the UK.
What do ministers say about this?
They are not very enthusiastic about what seems a rather zealous interpretation of the law. In particular, they will want Ofsted to look again at how "reward" is defined - which in the case of the two policewomen threatens to bring huge numbers of informal arrangements under the scrutiny of inspectors.
But it might also be said that Ofsted is simply carrying out the letter of the law as introduced by the government three years ago.
Big Brother gone mad?
The reaction so far has been negative. A spokeswoman for children's charity Kidscape said: "I think there must be people all over the country going, 'What?'" She described this as "bureaucracy gone mad".
This follows recent controversy where it emerged that a child protection vetting scheme would mean that more than 11 million adults in England would have to undergo checks before being allowed to work or volunteer in jobs that might involve contact with young people.