The convention says that they will be updating their cosplay etiquette rules just because of this type of clothing, which features various female characters from adult manga.
⚠️Currently updating our cosplay etiquette rules for 2020 and we’re not allowing ahegao clothing at our future events because we are an all-age convention.
And now, one anime convention in the United Kingdom is putting its foot down by outright banning these shirts.
Ahhh, the Ahegao hoodie, it has become quite a fixture in many anime events and conventions already.