I have a large list of "unidentified" talkgroups that I haven't submitted to the database (since they aren't confirmed). The issue with just using the nationwide db on the 436/536 is just that - if the stuff hasn't been ID'd, it won't show up to listen to! I agree that it's a busy system. I don't usually stop when driving by, but put the scanner in discover mode and find stuff.
My list also has radio IDs and such to try to find channels that different users frequent. I think all the 70249x talkgroups are security channels for different areas of the Casino. Radio ID 9001 seems to be dispatch for nearly all channels except for shuttles (they use radio ID 2001).
Sorry for the "non-table" formatting:
Talkgroup Sum of Hits Use notes
669723 1
702491 54 Security - London/Madrid?
702492 49 Security - Rome/Bejiing?
702493 16 Security - Belvedere cage/Vienna North?
702494 51 Security - NewYork/Cairo?
702495 53 Security - alpha 1?
702496 9 Security ?
702498 26 Security - Zebra? Transports?
702499 11 Security - Henry units
702500 15 Security Post?
703930 2
703931 9 Trucks/ticket issues?
703932 20 Drinks/Belvedere/Regal?
703941 1
703943 8 Door Alarm
703945 35 London channel? Player card assistance
703950 14 Machine Maintenance
703952 1
703953 34 Shuttles
703957 3
703958 3 Maintenance
703960 11 Laundry bag? Hotel?
703967 1
703968 13 Pumbing?
703974 34 Paris? Game maintenance
703976 20
703978 5 Game attendent?
703987 38 Madrid?carts/janatorial?
703988 21 plumbing?
703995 7 Shuttles?