My mouth dropped!
I can't believe she would not cut it for you. Or give you just a bit more.
I have had fabric 'cut' both ways. When they tear it it does assure it is straight on the grain, but if they measure it correctly they can make sure it is straight for the next customer.
I have a customer who prefers hers to be torn, the rest we just cut, but we also give just a bit more as we know it will either be trimmed or shrink and if you need a full yard for a project and it isn't quite enough you are sunk.
I know MaryJo's in NC tears there fabrics and I have and no problems with it.