Well, it looks like you are ignoring corners....

 From the sometimes useful [manpage](https://linux.die.net/man/1/xautolock)    


   The xxxx argument to the -corners option must consist of exactly 4 characters from the following set: '0', '+', '-'. Each one of   
these specifies what xautolock should do when the mouse enters a small square area located in each of the corners of the    
screen. The corners are considered in the following order: top left, top right, bottom left, bottom right. A '0' indicates that     
xautolock should ignore the corner. A '+' indicates that xautolock should start the locker after secs or altsecs seconds (see     
below for the difference between both), unless the mouse is moved or keyboard input is received. A '-' indicates that xautolock     
should not start the locker at all. The pixels argument specifies the size in pixels of the corner areas.