I believe it was used as a garrote at times, but was it used in other nonconventional ways?
I ask because my grandfather served in the European Theatre during this time but rarely spoke of it. However, I vaguely remember a story I was told involving piano wire. What little I remember, he was riding atop a tank through an urban area. The tank was coming to a stop, but, as it was doing so, a piece piano wire strung between two buildings began to dig into my grandfather's neck. I was told that had the tank been moving with some speed he would have been severly injured.
He passed away when I was young, so I'm not if this was something he told me, if it was a story embellished by a family member, or just something I misheard as a child. Any clarification on this would be greatly appreciated!
I don't know if I have run across any instances of injuries from wire being strung across a roadway. However, I do know that jeeps and other vehicles were modified (in the field, I don't think any came from the factory like this) to have a wire cutter at the front. The linked page has some pictures you can look at. These were usually a piece of metal affixed vertically from the bumper, sometimes with a top portion angled out from the front of the vehicle. What I can't say for certain is that this is a response to actual injuries, but given that these modifications were fairly popular we can deduce that there were at minimum stories of such injuries.
Sorry I don't have more information for you, perhaps another of our experts will enlighten us both.