It is said that "this tool will only combine features that have the exact same X and Y centroid coordinates." My question is, is there any difference between X and Y centroid coordinates and X and Y coordinates? I'm asking because in the illustration pictures provided by Eris, you can see the output has one more dot than the input. At first, I though the Collect Events Tool was simply designed to calculate the number of overlapped points. But now it doubt it.
I have marked the extra point with a circle in the attachment.