It's still tied to Verizon, but as I mentioned before, its pretty easy to skip the activation. If you never want to use it as a phone on a network, then you just keep it on Airplane Mode.
On the Verizon prepaid Moto G, here's how you skip activation:
1. Power on for the first time.
2. Start going through the Setup Wizard.
3. When it gets to the Verizon activation screen, swipe down from the top of the screen to get the notification panel. With the notification panel down, you should see the navigation softkeys appear at the bottom. Tap the Recent Apps button.
4. You shouldn't see any Recent Apps--the screen should be blank. Tap anywhere on the blank screen, and it should dump you to the homescreen.
5. Once you're on the homescreen, swipe down from the top with two fingers, and turn on Airplane Mode. That should prevent the phone from bugging you to activate from now on.
6. After Airplane Mode is turned on, you can still turn on wi-fi or Bluetooth.