When I lived in Riverside I used to go downtown to an old (somewhat famous in this area) hotel trying to get my chops down at night. Most people are courteous, some I have to keep an eye on till they go away. The hotel has a bridal window display that I like to shoot. If you'd like to see a bad pic do let me know. Security (guys in suits with wires in their ears) usually come out to "get a feel for me". When they or anyone askes what I'm doing (?) it never occurred to me to reply 'artistic endevour'. I just say it's my hobby and that seems to satisfy. But if someone asked me to move along then I'd move along. What do I care? I would guess if you don't seem suspicious (looking around like you just shoplifted something), are of middle eastern descent, or photographing a federal building you're probably safe.