I am running a hotspot analysis on polygons assessing spatial clustering of decreases/increases in the population size of a particular bird (the increase or decrease is the weight, I am using the CONTIGUITY_EDGES_CORNERS Conceptualization of Spatial Relationships). Problematically, I have two polygons with zero nearest neighbors (no overlap, edges/corners touching--think islands). The optimized hotspot analysis runs without any issues, and one of these islands emerges as a significant cold spot. Are these results valid, or should I exclude these polygons from the analysis and only use contiguous polygons? Thank you!