Hi BEN KENOBI! Yep, you can duel with them. I've dueled with mine and never had a problem. And I've seen many videos (including videos from Germany) of other Hyperblade customers dueling with their Hyperblades. So far I've never heard of a customer ever damaging any LED's from dueling. There have been a couple of customers that have had a short in their blade ... but those are easy for Jim to fix and he does it for free.
The Hyperblade LED boards aren't like MR ... they are in sections making them able to absorb lots of impact with no resistance. Basically, you don't have to worry unless you plan on trying to smash the blade against light poles or trees as hard as you can over and over again. If you are just looking to duel or bang the blade against stuff you won't have a problem.