Yep, my girls are still harnessed at six and will stay that way as long as I can! We have hbb, but I hate them, because my girls can't buckle or unbuckle in them...three across, but with the harness no problem!
I think my daughter was nine when we got rid of the booster. I guess I dot have an elementary school kid anymore. Lol. I never really left when she hit middle school.
Mine is still in a harness. He will be 6 in May but hes not even 40 lbs yet. Legally he could have been put in a booster over 2 years ago but I'd rather have him on the harness.