We it was the older scanner since my wife is blind but I forgot to remove it and no alarms.
I've worn a ~180g stainless necklace through without it going off... but that must be getting close to the limit because it did go off while I was wearing my belt at the same time (metal buckle, not sure of the weight but it's not huge).This is most likely because of its weight and size. Even if it was the stainless steel it is less than 20 gr of metal. That probably does not trigger the the alarm.
I have left my 42mm Watch Sport "on" for the past year and I have flown dozens of times to US and European destinations without any problems. I am Pre-TSA, if you think that matters.
By the way, screw the TSA.
I paid for Pre-TSA because it saves me from waiting in the long lines every time I travel. You can screw them or you can pay $85 for five years in the fast lane.![]()