Hair coming out... oh yes
Me and my daughter own some BAB plushies too and their hair ... oh my...
So, its Rainbow Dash´s (my own pony) and Fluttershy´s (owned by my daughter) first birthday today and what can I say... Dashy looks as great as ever because she wasnt played with at all. I very gently cuddled her but most of the times she sits on my shelf above my bed. Fluttershy looks alright too, she has been played with but my daughter is veeeeeeeeeeeeeery carefull with her plushies and keeps Fluttershy´s hair braided so it wont tangle too much. My daughter´s Luna though... her tail came out the very first day she owned her and her mane has been getting thinner week by week I think. Luna keeps now sitting on the side of my daughters bed, hardly ever touched. I feel sorry for my kid that she has to keep her hands off her pony to preserve her beauty... its a toy and it should be played with without looks nasty or loosing hair right away.
I also own a Pinkie Pie which came with really nasty hair (Ebay, her previous owner had tried to give her a more TV accurate looks...) and whatever I tried, her extreme curls did not come out.
I guess BAB hair isnt easy to treat. For ponies that are for kids Id reccomend to braid the ponies hair to preserve it... you can open it for styling and then braid it when the kids go to sleep. Thats what we did with Fluttershy and her hair still looks fine