"is there any chance that test could be removed/made dependent on some label?", it sounds technically doable. 

But I don't know whether it's right to do it. Waiting for @richard's opinions.

It's preferable if the devices can be re-keyed with dev-signed
firmware.  If that's too labor intensive, or if there's some
reason they need to be in dev mode, we can add an exception based
on a label like the pool label.  That's already done for a few
other verifiers and repair actions, see here:
    https://cs.corp.google.com/chromeos_public/src/third_party/autotest/files/server/hosts/cros_firmware.py?l=91

#2: Thanks. I'd really prefer not to have to pick up the 9 devices, open them, and flash them with a new firmware... It's also more convenient for us not to have to do that when we replace devices.

Are we (crouton devs) the only ones with non-managed devices in the lab? If so, I guess we could match pool:crouton, if not, we could apply some other label to our machines and match that.

Matching pool:crouton should be fine.  You'll want to make
sure that the devices can't/won't accidentally get relabeled
for other testing by whoever is managing the chromeos1 lab.
I assume that that's already been done, though.

I note that the devices are already ineligible for the
managed pools, because they don't live in a lab in Stierlin Ct.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/5184c0cc86471f41ae8920af77a922483cb9c964

commit 5184c0cc86471f41ae8920af77a922483cb9c964
Author: Nicolas Boichat <drinkcat@google.com>
Date: Mon Mar 13 09:54:14 2017

autotest: Allow device in some pools to be in dev mode

This adds a new config option "pools_dev_mode_allowed" that
contains a comma-separate list of pools whose devices are
allowed to be in dev mode (e.g., running production firmware).

This is useful for self-managed devices in high touch lab, such
as the ones in pool:crouton.

BUG= chromium:700200 
TEST=Devices in pool:crouton can pass repair/verify stage.

Change-Id: Id9dbe90a84e32f7de3d81befe119c913df273488
Reviewed-on: https://chromium-review.googlesource.com/452858
Commit-Ready: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Xixuan Wu <xixuan@chromium.org>

[modify] https://crrev.com/5184c0cc86471f41ae8920af77a922483cb9c964/server/hosts/cros_repair.py

Our pool:crouton devices are running tests now. Thanks!