Based on the number of points and how spread out they are, this tool creates a fishnet mesh to overlay your points. After counting the number of points that fall within each fishnet square and removing squares with zero counts, there were fewer than 30 squares left. This tool requires a minimum of 30 counts (30 squares) to provide reliable results.
If your points occupy very few unique locations (if there are many coincident points), a good solution is to either provide aggregation areas that overlay your points or provide bounding polygon areas indicating where points are and are not possible.
Another option is to specify an analysis field. However, this changes the question from where are there many or few points to where do high and low analysis field values spatially cluster.