  Theoretically, the coordinate measurement of two identical particles at a
point by two narrowly separated narrow detectors, is interpreted in the limit
of shrinking width and separation, as the detection of two particles by a
single narrow detector. { Ordinarily, the ratio between probabilities of point
measurements is independent of the width of the narrow detectors.} We show here
that not only this is not the case, but that in some scenarios the results
depend on the way the dimensions shrink to zero. The ratio between the width
and the separation determines the detection result. { In particular, it is
shown that the bunching parameter of bosons is not a well-defined physical
property. Moreover, it may suggests that } there is a difficulty in quantum
measurement theory in the interpretation of coordinate measurement of two
particles.
