I'm beginning to think that tarps also indicate ownership, that the pile of leaves on the boulevard covered in a tarp indicates that you have intentions for these leaves, they are yours, they aren't abandoned leaves. 
These pipes in the yacht club parking lot ought to be fine in the rain; no one is worried that water will run in the ends, no, the tarp appears to tidy them up.  The sight of a bright blue tarp is preferable to a pile of pipe lengths.  I find this a bit curious, but clearly I don't quite get the nuances of tarpdom yet. 

I grew up here and can't ever remember tarps everywhere.  Dark mildewed canvas, yes, and tarpaper, lots and lots of tarpaper.  There was a small house on the way to school that was only tarpapered.  It is now stuccoed, but for twenty years the tarpaper did its job.  Now it would be neatly faced with bright blue plastic.