I have a silver (violet) toner put on my hair every time I have it highlighted to stop it looking brassy. I'm naturally blonde and have it highlighted to brighten it up a bit. Completely normal if you want to remove yellow tones from your hair! I prefer a softer look. I buy a violet shampoo to use at home to use in between too. It's all to do with the colour wheel!
Hmmm, sounds a bit weird to put it on a natural strawberry blonde. I am naturally a tasteful shade of mouse. I sometimes use a violet rinse and shampoo /cond to keep my ash highlights from going brassy. But ive only ever seen it recommended for chemicaly treated hair