I just had my AT800-DE replaced under warranty and there are hand etched numbers just below the actual serial number. I asked the pro shop why this was and they said Yonex just started to do this and Yonex did it to all the return rackets they received. Anyone else experience this?
For their record purposes i guess that the the owner of this racket has had a racket replaced under warranty. But i never had this happened before to those that i've exchanged under warranty.