I traveled to 3 islands for my Bday. I have TSA Precheck. Also have had a knee replacement in the past. At LIH/KOA and OGG I was delayed while using Precheck. These airports do not have an option not to go through their old scanners--so expect a full pat down and delays waiting for the opportunity to do so. I was chastised at KOA for not "telling someone" before I put my carryon bags on the scanning belt, and thus they would not take me to the full body scanner because I put my bags up already. The other airports said they have no option but an older scanner and a full pat down (at all TSA Precheck lines). For all the airports I have flown on the Mainland, I put my bags up (as previously directed by TSA) and then let them know why I will set off the old scanner--I am then led to the full body scanner. DON'T expect this in Hawaii. If one does not want the delay, I was told I would have to just use the regular lines and can avoid not taking my shoes off by letting I know I have Precheck (only benefit).
Now, maybe I should have known this about flying in Hawaii, but did not, so am sharing for anyone who may have a similar situation.
Now, maybe I should have known this about flying in Hawaii, but did not, so am sharing for anyone who may have a similar situation.