There are things for which disused=yes is still appropriate. Especially when a disused lifecycle prefix would cause them not to be rendered. One such is a quarry. It’s still a visible landmark. Unless there has been some attempt to return it to nature by (for example) planting trees, it may be difficult to distinguish, on a Sunday, between a disused quarry and an active quarry where nobody is working and all the vehicles have been locked up in garages. It’s still possibly dangerous to walk near the edge.

I’ll also point out that in the UK maps from Ordnance Survey show disused quarries with their name (if known) and “disused” in the label.

It is almost certainly NOT (as others have suggested) bad maps, out-of-date maps, or bad routeing.

Here is the most likely (almost certain) explanation.

Most satnav systems give the user three option (sometimes more).

1) Shortest route.

2) Fastest route.

3) WALKING route.

Guess which one leads to idiot drivers ending up on goat tracks…

Then again, the comment from davespot indicates that maybe Tom Tom gets it wrong, but the link doesn’t work for me so I’m not sure if it implicitly went for a walking route.