A Risk assesment is used to check your Accessibility around the property, checking for trip hazzards, ie kids toy's garden furniture and orniments, slippy decking (especially) on wet days. this includes your access to windows were you would struggle to get to a window, say above a conservatory or pitched roof. its all for yours and the customers safety.
if the obsticals can't be removed to protect your safety then don't do the window/s