I don’t understand how paying for a seat in advance will help you escape a baby? Sure you can pick a seat away from bassinet seats, but often the bassinets in the next cabin are very near. Parents may choose not to have their child in a bassinet or the child could be 25 months and have thier own seat. I’ve never paid for seat selection in CW myself as I’ve always travelled as a couple. On a 747/777 we’re highly likely to get a middle pair. Travelling solo on the same aircraft is a different matter, on an overnight I wouldn’t want to be next to a stranger.