I know of a few teams that use TQ to make an ... ehem... enhanced "smoke" ring on their briskets. I attended a brisket class at a comp in Colorado taught by a VERY highly regarded competitor and restauranteur who taught us the technique. Only time I ever did it was when I did my great TQ experiment a couple of years ago and TQ'ed HALF of a flat while leaving the other half clean, just so I could get individual slices with the TQ effect on one end and only true "smoke" ring on the other. You can't tell a TQ ring from a smoke ring by color - I can mimic the deep red-purple color with changes in wood and cooking techniques. The main difference was that, while the smokering on the REAL smoke-ring side of the brisket slices was of nicely even depth and the inside demarcation line of the smokering was smooth, the TQ-enhanced side was of uneven depth with a more jagged demarcation. This was evidently due to the uneven absorption of the TQ chemicals through the pores of the meat.
The same chemical processes occur whether one makes a smokering with smoke or with a curing agent. Though one might be able to tell the difference between the two visually they are in effect the same thing.