If I'm dubious about the safety of a location I leave the bag in the hotel, strap the camera over one shoulder and under my jacket so it hangs comfortably out of sight when I'm not using it, and anything else I need goes in an inside jacket pocket. Only works with small lenses, of course!
With bigger lenses, you could pick a beaten up old bag instead of an obvious camera bag, and add a protective insert for the camera stuff. Something with no outside pockets and single zippable opening works well - then you can use a small padlock to prevent wandering hands in dense crowds or if you need to stow it overhead (for example) on public transport.
Some percentage of this is certainly paranoia - but not 100% of it, and it doesn't do any harm.