in my experience, using the same move from the same character is a really easy way to do one of two things (depending on what time of player you are playing against):
1. a player who is not very good - if they can't figure out the proper counter move, they get mad and either quit or stay bitter for the rest of the night
2. a player who is really good - they just beat you into the ground
so is it cheating? no.. but someone will end up annoyed lol