I would hope not, and BTW I would call a four year old a preschooler and not a toddler. Sometimes kids under two are free, for example to fly as a lap child, but not so if they've passed their fourth birthday. In this context, 4 = 11.
If you use the PP website search for lounges feature, the specific rules for a particular lounge appear. Sometimes kids under 2 are free, and this would be specified there.