Ruskie,
I was doing a family tree for a friend as a gift & was able to purchase the marriage cert. of the parents to get back to the next generation as the people in question were still alive i.e. the mmn wouldn't be on the index of deaths & I had no problem.
I also have a BC of someone born as late as 1950s which has 'Adopted' on their record!
The child was adopted 'by' another family, rather than being adopted 'by' the 'birth' parents named on the BC.
I ordered that cert. in the same way as the marriage above, both not being downloadable, wait for it...
Because of the 100 yr birth rule & 75 yr marriage rule

I don't actually see the difference of being able to purchase yet not download the certs?
The only difference is the price if compared with the privacy rules which could be incorporated for those later certs.

Annie