I have travelled extensively all over the world and have carried up to $18K with me in places that were much sketchier than Vegas. Of course, I've been to Vegas quite a bit, too. The most important thing is common sense. Be aware of your surroundings or make sure that aware people you trust are with you (if you decide to get wasted or something of the sort).
I don't know anything about hotel safes, but I always kept my money on me, as suggested earlier in a discrete money belt. I only take it off while travelling. A dummy wallet is also a good idea, as earlier stated. Traveller's checks will cost you money, but the 1% charge may be well worth the insurance and they're as good as cash once you make it into the casino. Never tell anyone where your money is, or that you have a lot of it. Always check your rear-view mirror or look over your shoulder when you are departing from a situation where people have seen you with a lot of money (a common occurence in Vegas.)
One note about a money belt: being that it's own your body all the time, it gets really, really funky. If you're a heavy sleeper, there may not be much you can do about this, as you'll need to keep it under your pillow, unless you are in a hotel, in which case you likely have a deadbolt ot your room. Powder your money belt with baking soda every night. This helps a bit. If you sleep lightly, hang it up, powder it with baking soda and make sure that it is exposed to sunlight for half an hour if you can.
You can also carry a method of self-defense, like mace, a taser or a firearm. Nevada has very liberal gun laws and will recognize an out-of-state concealed carry permit, according to a police officer I spoke with. Do not do this if you are not already comfortable with firearms. Check
www.nra-ila.org for current gun laws.
As far as carrying cash, you do have to declare amounts over $10K when travelling abroad. Furthermore, you can have such amounts confiscated by law enforcement within the country if they have reasonable suspicion that it is the proceeds of or is used for drug trafficking, money laundering, etc. This is not likely to happen in Vegas. Outside of Vegas this is also easy to deal with if you just keep a tax form with you or a notebook with your live winnings records and explain that you are a poker player. This type of trouble is unlikely, since any cops you run into are not likely to be from an agency that deals with these types of laws. Still, asset forfeiture laws are strongly written and "innocent until proven guilty" only applies to incarceration or fines, not to confiscation, so be safe, not sorry.
Finally, chips are safer than cash. If your chips are stolen, there may be some hope that the culprits will be caught trying to cash in high-denomination chips. I believe that many casinos are starting to put RFID microchips into their chips.
The number one way to prevent theft, though, is good common sense and awareness of your surroundings.
Last edited by g_murder; 02-26-2008 at 06:30 PM.
Reason: proofreading