Possibly the red dye protects the fabric from UV degradation so the red stripes end up stronger or stiffer. Then flexing of the flag in the wind would cause stresses along the edge between the stripes.
OK, bumping this because I finally got some pictures.
One
Two (and a different shot)
Three
Four
In my experience, the US flags that I see flying all tattered are ones that have been left flying for months (not taken down at sunset, not lighted at night), just hung and ignored. Those people don’t fold & unfold them at all – just leave them out in all weather, to fade & get tattered.
(And I too wound need to see evidence that this actually happens to non-sewn flags.)
In the first pic one white stripe appears to be torn right down the middle.
Nonetheless, assuming your assertion is right…
I’m going to assume the only time that it will happen is on nylon flags that have been heat printed. The printing ink might bind the red stripes together and the heat along the edge of the stripe might weaken the material not coated.
A tear between two stripes, but another tear in the middle of a white stripe.
If you zoom in on the flag on the left, you can see bits of white on the red stripe, and bits of red on the white. Also a flag that has torn vertically, and two that have torn, or are folded diagonally.
The other two are lacking in detail, and curled up, so that it’s hard to tell if they’ve torn cleanly along the stripe or not.
This is not good evidence for your claim. Please try again if you have some better examples.
For the red stripe on the left. the seam conecting it to the white stripe is coming undone.
Flag 2 (the one above the Rally’s) I wasn’t able to get close enough to be sure, but all the rest of these are definitely all one printed piece, not seamed together. For #2, look especially at the right flag, and at the end, not the bottom: Every single juncture of red and white is partly frayed.
And yes, the first one does have one tear in the middle of a white stripe, but also at least two right on the boundary between stripes.
So, confirmation bias it is, then.
I took those four pictures in the span of two days, and that’s most of the non-stitched flags I saw in that span of time. And even one tear along a stripe boundary would be significant, because it wouldn’t have to be very far off of the boundary before the deviation would be perceptible. With multiple flags, all showing multiple tears exactly along boundaries, something has to be happening.
This little guy is an interesting case: https://www.alamy.com/stock-photo-tattered-us-flag-125504888.html On the lower right side there’s a consistent line where the fabric starts to fray (the boundary between damaged and undamaged fabric), regardless of color, but the frayed red stripes are longer, suggesting there’s some small amount of reinforcing coming from the printed ink. It may not be enough to stop the fibers from separating, but it’s enough to stop the fibers from breaking off so soon. The second red stripe from the top however is much more intact than the white stripes. This is all contingent not only on the construction of the fabric, but also the type of printing process and inks used. In this particular case though, the ink itself does seem to provide some benefits over the raw fabric.
I’ve often wondered the same thing, so it isn’t just in your head. I’ll try to snap some photos of similar flags around here.
For the others: Chronos isn’t claiming that wear isn’t occurring in other places, but that there is definitely a mechanism that causes separation along the color boundary on flags created from a single piece of material.