That is what Cloudflare is doing. Using a Cloudflare security product intends on modifying the website it's proxying. Everyone involved in running the website -

That is what Cloudflare is doing. Using a Cloudflare security product intends on modifying the website it's proxying. Everyone involved in running the website - the original website owners and Cloudflare, intends for this to happen. The one exception is Cloudflare turning this on by default for free 'customers', but hey, if you're not paying really what leg do you have to stand on?