I had checks printed up that had that wording with a URL pointing to a page of T&C. It was the same language that was on my phone / cable bill. The checking account and the page are long gone, but it only had a couple of clauses. One was that this agreement overrides any other and that my ISP/web host was to notify me in writing via certified mail and allow a 2-week grace period before taking my account down for overages. They had a habit of preemptively taking down my site if I reached 85% of my bandwidth before the 15th of the month. And it was only down for the internet at large. Anyone on the ISP, including me, could still see it fine, which was very frustrating.

They always cashed the checks without complaint but I moved to a better hosting company about a year later and never got a chance to invoke the "agreement".