We're pairing! Like - almost all the time. I'm really enjoying it, but as we tend to not always pair on the same machine, it takes time until the setup converges to some standard which is accepted by every potential pairing partner.
One of the most annoying things I've encountered is keyboard layout switching. Like 80% of the time that you switch from the driver- to the navigator-seat, or vice versa, you forget to (use some arbitrary, machine-dependent non-automatism to) switch the keyboard layout back to what it used to be before. This can range from varying keyboard shortcuts (Alt+Shift+Ctrl+F1+F12+CAPS+F) to raw setxkbmap calls.
Long story short - use the power of X11 to set a keyboard layout per connected keyboard, and enjoy the whole pairing session without a "WTFIHATEYOURMACHINE!" once!
DISCLAIMER: stop your energy pointing me to udev! kthxbye.