Since these situations are cropping up on photo walks, here are some ground-level suggestions for individual volunteers or groups embarking on these:
1)Familiarize yourself with 'photo restrictions' in your city/state: These may differ, and none of us know all the restrictions in each state - maybe a news photographer or someone could be asked in advance, since we seem to have good media contacts in India in general? (Tinu or anyone else: do you think there is someone who could help provide this info? We are all ignorant here. Individuals would feel more confident if they knew whether or not what they are doing is illegal.)
2)Stand your ground to the extent possible: Keep asking which law is being applied if any police action - charging with a case, arrest, confiscation - is brought up. I know this is very very hard to do when faced with police personnel, but still. The police are less likely to bully someone who can firmly ask questions - and who does not get intimidated by the law.
3)Create a chain of 'help': Call another wikipedian for help - if there are 2-3 or more wikipedians present, divide up tasks, so that one-two people can engage the cops while another makes phone calls. When Pranav called me, I in turn called lawyer friends who clarified that P&Co were not breaking the law. I then felt more confident to ask them to 'stand their ground'.