Alice Blue Gown
A campy term for someone who is a cop
or is dressed as a cop
-1970s-
from the title of a 1919 song about the daughter of President Theodore Roosevelt,
who was famed for a dress she wore.
"Gentlemen, be forewarned that we expect a visit this evening from Alice Blue Gown,
so we remind you not to be seen touching anyone while there's a pig in the building, and absolutely no dancing"
or, conversely,
"Oh come here you big burly Alice Blue Gown,
search my body cavities, and handcuff me, already!"