u/TyrannosaurusPlofkip

I'm considering a Flow 2 with the Compact Dock for my home.

Single-floor home, no stairs anywhere. Dark tiles and light-colored carpets throughout, plus flat dark grey dirt-trap mats sitting flush at tile level.
My home is already robot vacuum proof: my previous tenant was a Roomba i7, and while I tried a new 705, its navigation- and software quality were a disappointment, hence my preference for the Flow 2.

Two questions:

1. Stairless Mode: Since I have zero stairs, I plan to leave it on permanently so cliff detection is ignored (kills the dark-floor cliff-sensor issue entirely). Anyone actually run it permanently? Any side effects, or is it cleanly isolated?
2. Dark mats: I'll set them as no-mop zones, so mopping is handled. Narwal's support docs used to mention the underside ultrasonic carpet sensor can misread dark/black surfaces (I can't find the page anymore — possibly moved, possibly because it's no longer an issue). How does the Flow 2 specifically navigate flat dark mats — maps them fine on first pass, crosses smoothly, doesn't misread them? Does that ultrasonic issue actually show up on flat low-pile mats, or is it a thick-carpet thing?

Flow 2 owners especially — thanks.