I agree with Holice that the worst problems are with the wide backings. They are folded and folded again on the bolts, which just magnifies the issue.
When we sell backings, we tear them, adding an extra 3" to compensate for the weakened edges.
Everything else, we cut. Carefully. There are a lot of quilters who would be horrified to get a piece of fabric that had been torn. (I think there are definite regional preferences with regards to this issue.)