The vast majority of folk tunes in print use use

A:|
B:|

to mean AABB. That may not be the "normal rule" for classical music but it is for the kind of music ABC is most often used for. (It's a house style first adopted by Nathaniel Gow, I think. O'Neill used it all the time 100 years later).

I have hundreds of tunes on my site encoded that way I'm not going to change them because some developer is too damn arrogant to fix bugs.