At my last place, one of our customers had more than their share of power cuts - most of them planned and pre-notified. One day, I took a phone call from them to ask about using a widowmaker - though they didn't know what it's called until I told them and explained why.
The reason they asked was because their neighbour rented electric mini diggers and a 'kin big diesel genny for running them whete there wasn't a suitable supply available. The neighbour was used to just knocking off the main switch and using a widowmaker with big red plugs on it. They'd suggested our customer could share the genny and use a widowmaker as well.
Apart from safety, our customer didn't have any 3 phase sockets, and their circuits were spread across 3 phases. I persuaded them to have an inlet and changeover switch installed - which was done in a rush as a scheduled power cut was only 3 days away.
On the day, it didn't go quite to plan. Therecwere "wiring errors" and the genny tripped - plus their cables had no neutral wire even though they used 5 pin plugs
I was tempted to RIDDOR both the use of a widowmaker and the mismatch between cables and connectors. In the end I had to keep quiet or it would have caused problems with our customer.
I think the neighbour did install their own inlet & switch setup after I explained why widiwnakers are called that - it's not just having a plug with live pins.