Hmm. People are talking about how showing up on social media might be bad for Mari, but I don't think that will be too much of an issue, since there isn't much that could let people connect the post to her and it's not like she's a very online person. The biggest things she probably has to worry about are Momo getting overly pushy with pictures and posing or Kyouko finding out and getting worried or annoyed about the lies.
However, I am curious about whether one fairy getting her picture taken and posted might start to effect other fairies. In particular, I'm wondering if seeing one fairies true form might weaken the glamours of any other fairies; it's not like we have much information about why most people can't see them and why some people can.
If she turns into mini-Sei Shōnagon or (wholesome)Hunter S. Tomson I will be very entertained.
If she ended up being a regular Hunter S. Thompson, then I will be entertained
That would require an impressive knowledge of drugs, vulgarity, and generalized misanthropy for someone her age. It would definitely make an interesting juxtaposition to the rest of the story though.