Well think about it, if a simple ring would set it off, so would the snap on your jeans and various other things. My watch is hefty and weighs about a quarter pound of solid steel, along with a gold belt buckle and a pocket full of keys, plus rings I wear from time to time and in all my years of flying have never once set anything off.
Some sensors are very sensitive. For example a few years back by bf and I went to kings dominion (theme park) and his watch set off their security alarms. We were both shocked as this was our second time entering the park that day with nothing on us but money and id.