Here's the thing -- it's not "extra". You *must* sit next to your children if they're little. I am totally fine with making seat selection a chargeable experience -- if I'm traveling with my wife or friends we are happy to pay extra to choose where we sit and whether it's together. That's fine. But with my five year old it's not optional, period. So it's a parent tax, not an optional benefit. I'm flying Spirit in a couple weeks and I'm not paying to pick our seats, and I'll check in exactly 24 hours before the flight to (hopefully) guarantee me and the kids sit together, and if we don't I'm going to be on the phone with the airline right then. If they tell me to talk to the gate agent they're going to hear it from me, because it's their problem and they shouldn't put the onus on other passengers as people are boarding.