Green’s Dictionary of Slang

(US Und.) of a place, guarded by an all-night watchman who sleeps on the premises.

1924		G. Henderson Keys to Crookdom 53: He is familiar with the habits of officers and patrolmen and he knows whether the place is ‘kipped’.
1928		C. Panzram Journal of Murder in Gaddis & Long (2002) 116: To pull off a hot prowl is to turn off a trick in a private or a joint that is to be kipped or bugged; that is to rob a place where people are sleeping or that is wired.
1933		Ersine Und. and Prison Sl.
1950		Goldin et al. DAUL 117/2: Kipped. (Central and Western U.S.) Guarded by watchman, especially one who sleeps on the premises; (by extension) occupied by sleeping residents.