Green’s Dictionary of Slang

(US) one who arrives at the end of any situation, e.g. the paying of a bill, in time for the last dance.

1922		Edwardsville Intelligencer (IL) 14 Sept. 4/4: The Flappers’ Dictionary [...] Finale-hopper: Young man who arrives after everything is paid for.
1922		T.A. Dorgan in Zwilling TAD Lex. (1993) 36: (IS: Chatting about the finale hopper as he eases his way over to the dance hall for the last hop) I thought they called them cake eaters. No — a finale hopper is a jobbie who never takes a twist to a dance but who horns in on the last dance as the band is playing Home Sweet Home.