I spent multiple hours trying to finish this objective. The best solution I found was to set my alarm for 2 or 2:30 am when there is a low population on the server. What makes this objective even more ridiculous is that I counted over 70 machines in the Republic Nar Shaddaa casino that didn't have the cheat detection temporary skill enabled.
Edit: the Imperial-side Star Cluster Casino has well over 100 machines on the gaming floor, could the developers use those for the catch gamblers objective? No, only the 4 tucked away in another room with a 5 minute respawn timer. It's so stupid!