According to TSA PreCheck page[1] the same liquid limitations still apply, you just don't have to put them on the belt. I don't think this is about them being a

According to TSA PreCheck page[1] the same liquid limitations still apply, you just don't have to put them on the belt. I don't think this is about them being able to detect the threat liquids. For the security checkpoint throughput it is important to avoid having to stop people and dig into their bags. I believe the reason for picking the liquids out of bag is just to make it faster for the security person to check you are not carrying too much. For PreCheck flyers this is not needed, since most of them are seasoned travelers and now the limits. [1] https://www.tsa.gov/precheck https://www.tsa.gov/precheck