My friend, when the school of Hillel stated Shamai's opinion, they made sure to understand it first. I encourage you to take a look at the Shuchan Aruch (Yore Deah 97:1) were it states clearly that in order to knead a dough with milk you need to give it a unique shape and if you don't, the final product can't be eaten. The purpose of a kosher certification is to inform which restaurant, bakery, etc. sell products that can be eaten according to Jewish law, and only uniquely shaped bourekas meet this requirement.
Saudi king to meet with Obama on Friday amid Gulf concerns over Iran deal (Reuters)
from the article: Regulating the shape of bourekas makes a joke of Jewish law