Ah yes, I saw it now.
Advertising a €9.99 fare is now not exactly honest if you happen to be travelling with a child.
On what basis ?
Years ago when they had V cheap fares but kids paid £10 just booked kids as adults.
Never had an issue with that, notice nothing in the T&Cs regarding it. Can't book an adult as a child, understandably, nothing to stop booking child as an adult.
I have done dozens of Ryanair flights with family and never been assigned a seat apart at online checkin. Always got some combination of ABC-D or C-DEF without paying anything additional.
Still can book as adults.............. if not sitting together then it is at your risk.
Now under the new system, if all of us want to sit close together, it's a minimum of an extra GBP 16 per return (2 adult seat reservation per direction). Over 25 returns a year, that's GBP 400 for Ryanair. If you happen to make a very late booking when all the standard seats are gone, even your children will be paying.
Free to take your chances at checkin. So should Ryanair hold standard seats just in case someone makes a late booking for a family ?