Gravel navigation, and other times where you need to stay on route

Summary: a persistent, loud "route departure alarm" would be really useful while mountain biking or gravel riding, when straying off route could mean an extra 40 minutes of climbing back up a hill...

Background: Yesterday I went for a gravel ride in the surrey hills. I have several routes which all end up in the same place, by different trails. As i rode south toward the north downs, i had set my screen to the "power menu" to see how much effort i was putting in on some of the climbs. Eventually, I got to the top of the down and started my descent. I heard a few of the usual beeps, but assumed, as it had been beeping at minor turns that i was still on route.

It was only when i got to the bottom of the down that i realised that i had gone the wrong way. The Karoo had automatically rerouted while i was going down the hill, but that was little use now i was at the bottom of the hill. While it wasn't a particular problem this time, I could just imagine similar situations where I could be riding in the Yorkshire moors, I would absent mindedly get carried away, and end up carrying on down a big hill, when i should have taken a fork.

Sometimes, you really don't want to deviate from the predefined route.

Other than this one hickup, it worked well for the rest of the route!

Solution: An optional (on/off) loud and persistent "Off route alarm" for when you leave the predefined route, which you manually have to turn off. Once you return to the route, the alarm is reactivated in-case you stray off it again. This persistent alarm should be loud enough and annoying enough to be noticeable when riding down a hill!

Figure 1: Wrong way (Red arrow is route i took down the hill, instead of following the ridge).