We used to have a place that sold Bandag Retread Tires. Mostly LT for vans and pickups. But some car and occasionally a big rig. Supposed to be where core was inspected and was strictly enforced that the cores passed. I never ever heard of anyone having problems.
Looks like they are still doing it, but that location is no more.
My buddy had a shop close by and they were always busy.
My friend spent good money on a new set of circle track tires for dirt.
They were new tires used as cores and a special tread was put on.
I guess as long as the core is good so is the product.
As we all know other countries don't care like the USA does aboutstandards.