Over the last days, I had a few attempts of vandalizing questions/answers in my "approve edit" queue. This morning, it was the user "gnu" for three times and I wonder what to do about this. Just rejecting the edit helps the immediate problem of course, but I feel this shouldn't be all.  

Edit: 
With Iain's help I got them back, so here are a few examples: 

 - https://serverfault.com/suggested-edits/1463
 - https://serverfault.com/suggested-edits/1464
 - https://serverfault.com/suggested-edits/1465