It's still through the mail, regardless of circumstance.

It's not in person, because you didn't obtain it in person.

Perhaps it could be a TTM/VV.

More likely it's just Via Venue, since it really is just via the venue you're sending to, just like any other via venue attempt.

A thought occurred to me as I packed up some photos to send out.

Where would all of you classify autographs that you mailed in to an autograph show to get signed? It's sort of technically TTM, but could also be considered VV or IP. There are a few shows that I follow that allow you to send in your own items to get signed if you can't make the show and I've taken advantage of it in the past and just mailed more out to another today.

Just for curiosity's sake.