Don't shoot the messenger, C.
I know what they were doing at CdG and GdN in March. And assuming the cheese checkers are part of the same union, I'd easily believe they're doing it too.
Any customs man can check anything they want. Normally they just check the odd thing. But if Jean-Pierre Douanier wants to check the contents of every single package going to the good old Royaume-Uni, then he's allowed to.
I know it's confusing you that a froggie union member is actually doing his job properly instead of going on strike, but this is what Macron's done to the country.
I foresee a career for myself as a swashbuckling cheese-runner, sailing the Dover straits with my fast and weatherly three-masted sloop packed to the gunwhales with Boursin and bound for the South Coast with a damned Xebec full of frog Excisemen in my wake.