  In this note we stress the necessity of a careful check of the arguments used
by Vio & Andreani (2005) (VA hereinafter) to criticise the superior performance
of the biparametric scale adaptive filter (BSAF) with respect to the classic
matched filter (MF) in the detection of sources on a random Gaussian
background. In particular, we point out that a defective reading and
understanding of previous works in the literature (Rice 1954; Barreiro et al.
2003; Lopez-Caniego et al. 2005) leads the authors of VA to the derivation of
an incorrect formula and to some misleading conclusions.
