I think Yamaha is a BIG company and is flexing their muscle's .
I believe that it is OK to record a song using a style .
I think the only problem is the fact that another person could identify "how" your song was created . "Oh they must have used style such and such on the yamaha psr-whatever " .
Which musically isn't creating the style from scratch and there fore not being totally original !
BTW ......I believe that it's players who never owned an arranger keyboard ( and understund the functions)that give arrangers a bad rap ! If I record using a style , I make sure to edit or add to the styles ! Just like someone would edit a sample or edit a beat ! dano
my 2 cents worth .........