Limits & validation

Finding	Practical meaning
Pixel scanning has high false-positive pressure	Use broad scans for exploration, not as final maps.
Candidate/polygon workflow is much cleaner	Best operational mode for FKB field-mapping prioritization.
Increase-only scoring reduced raw false positives by about 10x in validation	Direction matters for construction.
S1 GRD intensity recall can top out around 0.3-0.5 for small buildings	Some cabins/houses are below the GRD signal floor.
Coherence can lift recall toward roughly 0.6-0.7 in current validation	Strongest optional recall lever.

Not a fully automatic building detector

A flagged feature means the candidate deserves review. It does not prove construction by itself.

Common confounders include wet snow, freeze/thaw, vegetation clearing, forestry, unstable existing roofs, terrain/layover/shadow effects, and reference-date lag.