If you've ever ordered the tacos at Chipotle (why?!) and watched them scoop the ingredients into the tortillas, this probably makes a lot of sense, although it's certainly possible that the amount of food you get when ordering the tacos will vary thanks to the seemingly unscientific measuring methods used on the chain's high-speed burrito assembly line. Either way, the former employee's suggested alternative to order tacos sounds absolutely brilliant and is likely the way to go.
Of course, this is just one person's opinion and shouldn't stop you from ordering tacos at Chipotle if you really want tacos instead of a burrito or burrito bowl that could potentially be a better value. But then again, when the people at the front lines of fast food sneeze guards say you shouldn't order certain things, you should probably listen.