Mandy is spot on (sorry - no pun intended!). Birth notified means simply that the parents were registered as pedigree. Pedigree registration of individual piglets is the next step - but only if appropriate, i.e. if the breeder confirms they conform to the breed standard.
I'm sure we've all had people coming back to us asking for the "meat" pigs (gilts) they bought six months ago to be registered as pedigree because they have got attached to them. That is why I always sell two boar pigs to complete newcomers, so they know they won't be able to hang onto them.
My answer, when anyone asks me to register a meat pig, is always no. If I sell something for meat, then it is because I have ruled it out as far as breeding is concerned. It will have had something wrong, some kind of unwanted characteristic, that made it not suitable.
It's always difficult reminding someone at a later date that they got what they paid for, but the truth is, pedigree breeders are trying to keep up the standard of our respective breeds - and, in some cases, to improve the overall standards.
Unfortunately, some breeders - whether for financial gain or through ignorance of/disregard for the breed standard - will register absolutely everything in a litter. The result is that sub-standard pigs enter the breeding pool and eventually pass on their imperfections potentially far and wide. All very sad.