Although the pair of Ortlieb Back-Roller packs on Mary’s bike make her look like a long-distance tourist, we’re actually on our way to her garden plot:

The left-side pack suddenly seemed unusually floppy:

One second later:

Another second and it’s visible under my right hand:

The view from her bike at about the same time:

I’m expecting to fall to my right, but it’d have been better if I hadn’t kicked the bag:

The pack went under the rear wheel and out the far side:

Where it came to rest in the middle of the trail:

Elapsed time from the first picture: just under 5 s.
Did you notice the other cyclist in the other pictures? She’s why I veered so hard to my right!
A pair of these latches hold the pack onto the rear rack:

When they’re properly engaged, they look like this:

When they’re not, they look like this:

Which is obvious in the picture and inconspicuous in real life.
The strap emerging from the top of the latch serves as both a carrying handle and latch release: pull upward to open the latches and release them from the bar, lift to remove the pack, and carry it away as you go. Installing the pack proceeds in reverse: lower the pack onto the rack bar, release the handle, and the latches engage.
Unless the pack is empty enough to not quite fully open the latches as you carry it, in which case the closed latches simply rest on the bar. We’ve both made that mistake and I generally give her packs a quick glance to ensure sure they’re latched. In this case, the plastic drawer atop the racks (carrying seedling pots on their way to the garden) completely concealed the pack latches.
Tree roots have been creasing the asphalt along that section of the rail trail: the bike finally bounced hard enough to lift the drawer and fall off the rack rod.
Memo to Self: In addition to the visual check, lift the packs using the strap across the middle holding the rolled-down top in place. Remember, don’t check by lifting the carrying handle, because it just releases the latches; another easy mistake to make.
Whew!
And stop drafting her. At your speed it doesn’t help.
Hey, sometimes we get into (the low) double digits where I can feel a breeze alongside her fairing!
Maybe some bright orange paint to increase the visibility of the lower part of the latch?
I’d convinced myself there was no clearance in there for anything, not even paint, but:


Properly latching it looks better:
That’s fluorescent orange tape, not paint, so we’ll see how long it lasts …
Thanks for pushing me off dead center!