HID lighting installation done years ago...1980's
All 208V ckts with 5 - 2.5A HID fixtures per 20A ckt, run in armored cable from common switching location (2 pole switches) to junction boxes in overhead where it is broken out into each light string.

The circuits in the armored cable are each run with like colors from TWO cables... 2 reds, 2 blacks, 2 whites. So, 2 - #12-3 armored cables carry 3 circuits with one phase of each circuit in each cable. Phases are NOT the same as it is a random pick of breakers in the three phase distribution panel.

This installation has been prohibited by the NEC for as long as I have Code books. (300.3(B) in the '05 Code)

Has anyone seen an actual problem in an installation like I have described?