[77T]

In the US the warranty is transferrable. What you need to know is whether the AD who sold it to the seller you're dealing with already registered it. In other words it could have only a partial warranty period left. No matter how many hands it passes through in the US, the warranty follows the watch. So you're not stealing anything.

If the AD never "started" the warranty, you have a bigger issue - how do you know it's not stolen property? You'd want the retailer to show you some provenance indicating it was purchased.