BTW these things also scan the genital area. If an unoperated trans woman passes through, it flags her for having a hidden weapon in her crotch. This has been a source of forced outings, public humiliation and in some cases outright sexual harassment by flight security staff ever since these machines where introduced at airports, i find the idea that somebody could be forced to endure that before every subway ride absolutely nightmarish.
btw a common way to confirm the victim's claim that the alarm was set off by girldick and not by a firearm is to do a patdown in the crotch area, with the gender of the person doing the patdown depending on the airport's levels of transphobia.