It's fine rationalizing it but how is that conceptually different from say Comcast saying: "Well actually your 100Mbps connection was just a first year promotional speed and now dropped to 20Mbps unless you sign another limited period contract. Oh, and actually, it's all for good reasons because the crappy modem that you rented at 10$ a month just kinda starts melting if it keeps transmitting at 100Mbps so we just saved your house from burning down. No need to thank us. Sorry we didn't disclose any of this to new customers but don't worry, just give us more money and everything will be ok."