I'm going to have to disagree.
Though the code text does not specifically elaborate, to consider an actual tent ... a temporary contraption covered in cloth ... to be a 'structure' makes as much sense as calling the Orkin Man a 'mass murderer.'
Then again, it's simply neither reasonable, nor possible, for any set of rules to spell out every possible variation. At some point, one needs to use some judgement.
Look at it this way: A local shopping center often has its' lot occupied by passing carnivals. While it's pretty hard to call the Ferris Wheel anything but a 'structure,' the parking lot remains intact - not completely torn up, as it would be if every ride was banging in ground rods.
Ditto for just about any job site. There may be a ground rod for that temporary power pole ... but the one for the building isn't there until construction is well under way. There sure are all manner of cords snaking about, though.
Now, I'm sure that. somewhere, there is a building official who is simply salivating over the prospect of selling permits the next time the Boy Scouts hold a jamboree .... imagine the permit fee income from all of those tents! ... but it's not going to happen.
To be fair, I have seen the term 'tent' used in different ways. For example, one of the casinos here has a permanent circus "under the big top." That roof may be canvas, but there's nothing temporary about this arrangement .... nor could anyone take it down with less than a month of labor.
That's why I focused on the true nature of the structure in my answer.
