I well remember in Chicago in the 60s and 70s that it was a common practical joke for someone to approach a home, a meeting and yell “Chicago Police” or “FBI” or “INS” or other police group.
I saw it when a non-political group was smoking pot; when a political group on was conspiring against the mayor; when the PSP and PLP were fighting among themselves; and when there was nothing happening but normal chit chat.
In all instances it was accepted as a practical joke...a joke that often got people uptight for a few minutes.
It is speculated that when the Black Panthers heard it... they initially thought it was a practical joke as they had heard it many times before as a practical joke. Indeed post Panther assassination others equated that practical joke to the boy who cried wolf.
Does that kind of practical joke still exist in 2023?
“SWATing” is a very dangerous sort of twist on this sort of practical joke. It can easily get people killed, both innocent homeowners (and their pets) and highly-strung, trigger-happy cops.