:::I suppose the warning can be kept on  since he did not explain his revert, but, as mentioned above, he removed a bad faith addition made by a clever vandal. It was said above by Jer757 "The information isn't "questionable" its pure vandalism by someone who is smarter than your average vandal." With that being said, his edit was actually in good faith, even though he did not explain his removal of content. 

 It is advisable to always explain removals, as, often times, content is removed maliciously, but, again, in this case, based on the information which I have now, the removal was done for a legitimate reason. 

 Thanks.