Wise said the Tramp reports were "dummy sheets" (arrest forms used for another purpose) and that only those booked were thumb-printed. The Tramps weren't arrested but were detained all weekend in case of questioning. "right after JFK was shot" fits in pretty good with the estimate of one hour after the assassination. The police activity in and around Dealey Plaza didn't stop at 12:30.
Still photographers were all over the area during the afternoon. Rather than capture the arrest of two sets of tramps, two photographers saw the one and only set of tramps.
"The officer photographed with the three tramps says they were released
THE SAME DAY & possibly just an hour or so after being taken to Decker's."
Wise says (20 years on) he thought he had been told that by a deputy (who probably didn't know himself and had lots of JFK witnesses to attend to). The three tramps were not held at Decker's; they were taken to the Police Department.