Some companies do. That's definitely a nasty pitfall that most customers would like to avoid. You'd have to review the specifics of the Grafana contract to find out exactly what is and is not covered. Patent infringement insurance isn't cheap, and they'd need it to cover their potential risk. With smaller SaaS startups, I can see how that might be an issue for them to cover.
http://www.aberlawfirm.com/2014/04/15/combination-exception-...