Cutting someones cord may cause you to end up on the wrong side of a pipe wrench.
If the guy wanted to get nasty it could also get you on the wrong side of the law. Over here, the deliberate and willful destruction of somebody else's property is legally classed as "criminal damage." I'm sure there must be similar laws in just about every state of the Union.
When I see a battered up cord I explain the dangers involved and suggest a remedy. If the damage is repairable by, say, just chopping off a couple of feet and reterminating the ends, I'll offer to make the repair myself in the interests of safety.
