Sonic is only charging new Fusion customers the mandatory-modem-rental-fee.
But combined with the new mandatory landline-dialtone service, its an effective $17 price increase - still a good value if you want home phone service and you're yielding 20mbps, but barely competitive with cable options if you're only seeking broadband.
TWC was charging the fee for new subscribers too, but look at what happened after that. :P