It remains that hardcore levels of costume play unsettle me. But I am also a massive Harry Potter fan/expert, so I am not sure where I am on this one.
I am sure Professor Sprout would not be seen in any of these costumes and would instead use the floo network to avoid the situation entirely. Nor would these outfits be suitable for trips down Daigon Alley.
Regardless, it is clear that there is an active Harry Potter costume play community for adults. It is amusing me that people would dress like this but still buy the books with the 'adult' cover on rather than the illustrated version meant for kids.