Losing (expensive) Avionic equipment is not uncommon. Miami is particularly popular due to lots of aircraft over a large area.
In once recent situation American Airlines suddenly found serial numbers that had been reported missing back in the system !! They had purchased their own equipment back !!
If you look at aircraft parked out in the back areas you will see a long steel cable, with a padlock, looped through all the avionic equipment in the rack.
Not fool proof but slows em down!