Sorry, not strictly relevant to the thread but I was thinking about ways laws can be abused and worked around, and if a case similar to the OP could ever happen in the UK. I feel confident in our child protection services that as soon as they became aware they would step in. However if the numbers were smaller, say half a dozen, and the commissioning parents stayed under the radar then I think it would be possible.
The main (?only) way we are able to know how many surrogate babies are in the UK is through court records of parental orders. Most hospitals don't keep records of surrogacy - I've sent FOIs to a few and they either cite privacy or state that it is just another pregnancy and no need to keep records. This means it is difficult for researchers to track them down. We cannot know, for instance, basic facts like pregnancy and birth complications and monitor the risks of gestational surrogacy.
The other thing about using parental orders is that doesn't reveal how many of the babies were born here in the U.K. and how many trafficked imported from abroad i think it would be revealed in the individual court records for each case, but that involves a lot of detective work and research.
Anyway what I am longwindedly getting around to is that I had remembered seeing somewhere that there is no obligation to seek an order. So there is no way of knowing if some people (perhaps believing the court process would not approve them?) simply live under the radar without formalising the parental responsibility. I think it would mean they couldn't get passports for the children and travel abroad but probably for the rest no questions would be asked and lies would not be queried.
Though having a batch of same age babies might raise questions.
I also saw somewhere that there had been one case where the courts refused a parental order but I don't know any more details about it, whether the commissioning parents had been found to be unsuitable?
"In the UK alone, the number of parental orders made following a surrogate birth has tripled from 121 in 2011 to 368 in 2018. The true number of surrogacy arrangements may be even higher, as there is no obligation to seek such an order."
Surrogacy: Why the world needs rules for 'selling' babies www.bbc.co.uk/news/health-47826356