Most places block pre-paid cards for purposes like this (although I have seen Stripe report a card initially as non-pre-paid and then later revise it to say pre-paid).
But do they block temporary cards generated by Monzo?
As far as I am aware Address verification is the only way to perform a fraud check and block prepaid cards. Maybe stripe can use some collective intelligence for certain card numbers but it would be a lagging indicator of fraud.
Not really, there are different BINs issued for prepaid card.