Guess you talking about something like this google image...
![](http://www.expeditionready.net/images/1380293708.jpg)
Can't say I have ever seen one on my trips off-road here on the East side of the US... Paul Ryan from Australia shows these at times on the forum - must be popular there keeping safe from the wild animals haha...
I do carry a tent with me all the times mostly for on-site storage... When the grandkids want to come with us they would rather sleep in a tent verses the trailer...
I also have the patio type cover that we like to setup over the picnic table...
Roy Ken