I can guarantee you that professional thieves have been told by their fences which models have passwords. They aren't going to hang around on a boat risking a cop walking by to unscrew a chartplotter that can't be sold. They'll just move one slip over.
And Garmin is no software slouch. Here's the description from Panbo about the password:
"Garmin explains that if the PIN is lost and the user can’t answer the reset questions — which are set during the process of entering the pin– the unit is unlockable, even by Garmin. There’s a very basic, chart-only limp-home mode in the event the unit can’t be unlocked. This mode restricts the unit to only displaying the basic chart with none of the normal features available. Garmin also emphasizes that nothing goes across the network, so multiple units on a boat each have their own PIN and there’s no chance of figuring out the code by sniffing the traffic on the network."
And Garmin is no software slouch. Here's the description from Panbo about the password:
"Garmin explains that if the PIN is lost and the user can’t answer the reset questions — which are set during the process of entering the pin– the unit is unlockable, even by Garmin. There’s a very basic, chart-only limp-home mode in the event the unit can’t be unlocked. This mode restricts the unit to only displaying the basic chart with none of the normal features available. Garmin also emphasizes that nothing goes across the network, so multiple units on a boat each have their own PIN and there’s no chance of figuring out the code by sniffing the traffic on the network."