A large roof, even a roof over a porch or deck, can often entice your tenants to use it as a gathering space. It's not uncommon in Columbus, especially around Ohio State's campus, to see numerous people hanging out on their roofs. This includes laying out to sunbathe as well as general gathering. More often than not, alcohol is involved.

This is obviously a safety issue, and likely one that is clearly prohibited by your lease agreement. If not, you'll want to add a clause prohibiting anyone from using any space not specifically designed for gathering.

For example, some roofs have decking and handrails as they are specifically made to be.