I've been burned by this myself since I still used an old Garmin far past its expiry date - trying to avoid a border toll while I was visiting Buffalo, it tried to send me the complete wrong direction and I only stopped when I noticed the arrival time said 9am and not 9pm... I was unfamiliar with the area so it would be easy to not realize my mistake, I only checked the device when it became obvious when I'd been on the road too long for what was supposed to be a shortish drive.
Similarly, in New Brunswick it tried to have me shortcut through an increasingly-rugged wasteland of logging roads. It took me an hour of backtracking to extricate myself from that. Fool me once, shame on you, fool me twice, shame on me.
I use Google Maps now.