A recent report over on MyDroidWorld suggests that Verizon may now be charging customers full price for phones under warranty, if you bring it back and it has been rooted. Supposedly, several users tried to return their phones for warranty work, but were charged the full price to replace the phones because Verizon determined they were rooted.
However, a separate report from Droid-Life that was tied to the same story indicates that Droid-Life was contacted by Verizon themselves and that Big Red denies that they even check to see if a phone is rooted. The representatives from VZW said they only check three things when a phone comes in for warranty, and rooting isn't one of them. Here's a quote from the Droid-Life article with the details,
Hmmm... we will keep a watch on this to see if anything different develops confirming either position.Our friends at Verizon saw this post and wanted to reach out to clarify everything immediately. First up, is the fact that their policy says absolutely nothing about checking for root on devices. When a phone is received, a phone is checked for three things and that definitely isn’t one of them. They check to see if the box that the device was sent in is damaged, if the outside of the phone looks awful, and if it powers on – satisfy all of those and they move on to the next phone. So basically, these reports of being charged for a rooted phone simply mean that these people were sending in garbage phone with defects.
Source: MyDroidWorld and Droid-Life