I'm guessing it's not me that's personally liable, but the company? The company I do the work for will have public liability insurance.
If outside of this company, I photograph a wedding for free, do I need public liability insurance? I have no business, there is no contract with me.
What about shooting live music for free
What about if I go down to the local park and take photos of flowers, put my bag down and someone trips over it..
I wonder where the line is drawn, why does everybody not have it - in case their negligence causes harm to someone..