If someone has commit access they can just set the bit themselves. I must be missing something about the flow or how the tools integrate with it. Could you be more specific with example workflows?

so, first git cl --tbr doeesn't work for Gerrit yet. For Rietveld, it's quite simple:
  add TBR=xxx@chromium.org to description OR --tbr xxx@chromium.org as cmd
  and then juts hit CQ or git cl land.

for Gerrit, first you add normal reviewers. Then you must edit TBR= inside CL message. Then after upload, one has to go to web UI and rather un-intuitive (for Rietveld convert) step LGTM-ing oneself. And then trigger CQ or run git cl land or git cl set-commit.

IMO, this has to be smoother.

 issue 626364  implements obeying TBR= in description, and hence --tbr-owners option of git cl, which makes life smooth, IMO.

also, FTR, git cl --tbr doesn't exist.

Hm, I wonder if anything has to be done here at all beyond 626364. I think not. Marking as dup.