The problem here is non responsible keepers.Sure if we hybridised in moderation and even labelled such as hybrids no problem.But there is too many members in the hobby that would try to sell as a pure bred in order to make a quick dollar.There would also be people naming the species with a new blood line such as EG: gtp x jungle "tiger lilly jungles" (due to the black barring over a greeny/yellowy background).Purchasers then think they have an awsum fazed pure jungle.They too would then breed and sell as a pure bred due to either not knowing or not caring and the chain continues.(we have already seen this with intergrades and childreni as well as jungles and diamonds).I like your labelling idea.It would more suit the actual breeder than any purchasers but I think its a good idea for your own knowledge.EG:If a customer comes back several months later with say a problem with the hatchling and you do not realise what purchase he made,the id number can then inform you of the parents etc.You could then maybe relate the problem back to them.
I think I may adopt a similar system as I sell my stock with a certificate I print up on the computer (my way of garunteeing quality) lol.