I live in Jersey City, NJ, where corruption is rife (the electrical inspector here is named Al Capone, I kid you not) and it's entirely possible that the building could have been built illegally and some official was fiscally persuaded to look tbe other way.

The plumber who came out to look at it thought it looked wrong at first, but when he saw that the other three units were done the same way, figured it must be okay. (He was a young guy...I guess a free estimate is worth what you pay for it.)

I guess now we'll get a second opinion from a different plumber.