I can honestly see both sides of this debate. It is "all in fun" but it also stigmatizes. In this day and age, it's important to be sensitive. No one - at least no one with any morals, IMHO - would go to a Halloween event dressed as, say, in blackface, carrying a watermelon, as was done 100 years ago in Vaudeville to portray African Americans as somehow inferior to whites. It would be extremely tasteless and very hurtful. Same arguement can be made about portraying people with MI as somehow dangerous. But, we also MUST be able to laugh at ourselves at times. So, I'm kinda on the fence on this. Overall, I say err on the side of caution.