That's not really good enough. It's unacceptable to let random members of the public use your services to "test" someone else's site. It's bad form let alone the breach of the ToS on 90% of sites.

It's actually a breach of our TOS also, that states you have to be the owner, or in lawful control of, a site to test it. I guess we might be able to push this message a lot more than we're currently doing though. Not many people actually view the TOS before running a test.