When I make baby quilts I prewash in hot and then wash the completed quilt in hot water prior to giving them away. I do it so I can tell the recipient that if baby has an "oopsie" that the quilt is designed to survive a hot water wash and in fact has already gone through a couple.
I did the same with the quilts I made for my DH's grandmother, who is permanently bedridden. Things happen (food spills, and other) and I wanted to make sure her quilts were going to hold up to lots of hot washes.