Depends on the tire's cost and the company giving the Warranty. Some of them exclude trail damage....which IMO, is the main point for a 4wd tire.
I've got some Competition Sticky Creepy Crawlers and frankly, cutting the tire is darn hard to do on that model....so I wouldn't bother to get certificates in spite of the ridiculous retail price (like over $900 per tire).
On my Pitbull Radial Rockers.....if it were reasonable....I'd probably get them since they were $450 per tire. Might talk to Discount about it since they will warranty offroad damage and if the tires are brand new, they'll sometimes allow you to get warranty through them....only problem is: I don't know that Discount even special orders Pitbulls.