> Based on what we've got now, I'd say minZoom and maxZoom should cause tiles within that range to be reused when the view resolution is outside of that range (I'm not saying that is what happens - minZoom is not handled at all - but just that they should be used to determine the range of z that is requested without constraining the view resolution or toggling the display of a layer).

This needs careful thought. Say the view is at zoom 0, and we have a source with `minZoom` 4. That means:
- the renderer will have to search higher zoom levels to find tiles to draw
- every increase in zoom level requires four times as many tiles to cover the same geographical extent
- so, in the case above we'd have to download 256 zoom-level-4 tiles to cover the same area as a single zoom-level-0 tile, that's a lot of tiles!
- you have to downsample a high-zoom tile when drawing a low-zoom view, downsampling is computationally expensive and can lead to ugly visual artefacts if not done carefully

So, I'm not sure that it's wise to use high-zoom tiles when low-zoom tiles are not available.