This is a very reasonable approach until somehow your competitors service loads twice as fast on the Vodafone Germany network.

As a business, at that point, you're basically extorted to pay the ransom or deal with a loss of revenue. Since the ransom is most likely lower it won't take long for your other competitors to start paying it as well leaving you with an objectively worse product, irrespective of your warning banner (which lefty Linda or Gradma Garry isn't going to understand).