Every voip provider that I "investigated" before deciding on Voipo started billing upon placing the order, that was about 6. I know Vonage did because I had worked for them and was also a customer. I know Net2Phone does because a company I worked for private labeled their service. Also a cable or service physically brings and installs the equipment so they have control of starttup dates. Since voip providers generally mail the equip to the customer (at no charge) this prevents a customer from getting equipment and "sitting on it" for weeks at a time before activating.

Not sure if Voipo has it noted during the signup process, if not, they should but that doesn't change the fact that all the voip providers (that I have seen/dealt with/worked for) do.