I sometimes run into people that:[list=a]
[*]Call themselves sensei and imply that I should as well.
[*]Are not any of my teachers.
[*]Train for half the time I trained or less.
I usualy let them be. I call them by their name. After I trained with them they suddenly avoid me. And I notice the spread weird rumors about me.
Probably calling yourself sensei can be one of the signs of a bigger problem.