Put simply, I believe this will become a security and/or a safety issue. Hopefully it doesn't take the occurrence of a serious incident before this ridiculous policy is reversed.
If now policy is that you must buy a seat to sit together, it must be spelt out clearly at time of purchase. That means eg. 'If you do not select seats, your party will be separated at check in' not 'sit next to X from £2'.
It is not 'normal' practice to deliberately split bookings so how can Joe public be expected to know they will be split up if they aren't explictly told?
It is deliberate misinformation, it is disingenious and seems to signal a return to the 'old' Ryanair who didn't get a single penny of my money for almost 8 years. AGB must be out of favour with management, perhaps they are worried their treatment of passengers is becoming too humane.