Up until recently, released talent from WWE can sign autographs with their old ring names. You see this at all the meet n greet shows
However, Dave Meltzer reported in the Wrestling Observer Newsletter that a new addition to contracts states that talent not under contract with WWE can no longer do that.
For example, if someone comes up to former Universal Champion Braun Strowman and asked for an autograph, he then would have to sign his real (legal) name. This of course is after his 90-day no-compete clause expires.
In my opinion, this has all the ear markings of the WWE possibly engaging with SAG Union in an effort to avoid any legal liabilities in regards trademarked names and characters. If this is the case, a sale to NBC Universal may be in the works.