In the event that you have a friend going to put up a circus tent, by all means, warn them.
I'd hate to think a family member or friend of these folks would cruise through this thread and read some of the comments made on it.
This is a time for sympathy, not explaining what a foolhardy thing these men did.
This was not a "circus tent". It was a large tent much like the ones that our Boy Scout troop takes to Camporees. I'm an Assistant Scoutmaster myself.
The poster made apologies in advance before he pointed out that it was a very dangerous thing to do.
In the coming year, at their next Camporee, you can bet your bippy that every Scoutmaster and Assistant Scoutmaster in America will be looking up for power lines before putting up their Troop's jumbo tent.
The rest of America would also benefit from such paranoia.