I don't want to get into trouble by posting a link to the website with info on the event (since there is a
travel agency involved in booking hotels and DL tickets). If you look up
disneyland martial arts festival on the internet, it will give you an idea on how large an event this is. This is our first year going, so I can't say for sure. I know the DL tickets they are selling are good for 2 days prior to the event and 14 days after. Also, each competitor gets a twilight ticket included with their competitor fee, which means that if the competitor is a child and they want to use their DL ticket, at least one adult would be purchasing an admission ticket.
Either way, no matter how many extra people it adds I wouldn't think it would be as bad as a summer crowd. I would just expect the normal crowds, instead of potentially lower SB Sunday crowds.
One potential slow down that I would expect would be longer lines at the security check points (where they go through your bags). The competition is at the DL hotel, and many competitors will have their martial arts weapons with them for the competition. DL security is aware of this, and is requesting that competitors be dropped off directly at the DL hotel instead of trying to walk thru DTD from the hotels on Harbor (where many people are staying). I asked directly, this is why I know. It is not like the event coordinators are sending everyone a note telling them this, so there will likely be many people trying to go through security Sat. morning (and throughout the day for that matter).
I'll just go and assume it's going to be crowded and hope for the best then. 
