After reading topic on macchiato...

When I first started learn about espresso coffee, started reading, eventually went to a barista hands-on course, etc.., I had an impression that theres a universal standard on what espresso based drinks are.
The more I learn, however, the more I realize that it looks like there are almost no standards at all in terms of recipes and volumes.
My question is, are there any written rules anywhere in the industry as to how make espresso based drinks.

I know that theres INEI and they define what espresso italiano is. However, I dont think theres such a thing as cuppuccino italiano or whatever...

I know that theres world barista championship rules, that prescribe what espresso is and what cappuccino is (though their cappuccino is different from any conventional cappuccino you are served in any country I have been)

anything else?
all these books we have here like "Barista techniques", etc. Are they binding at all?
if theres no industry standard for, for example, macchiatto, how can customer come and complain its not real macchiatto, if "its just the way we serve it here!"