Jeepers! Let's go one more time. Airlines have been providing assisted service for wheelchair & other disabled passengers since you had to catch a bloody pterodactyl to get from Laurentia to Gondwanaland!
OK, maybe not a pterodactyl. But what has changed to cause DJ to instigate 'apparent' restrictions over and above what everybody else does?
See my post No 1. It's cost-cutting. DJ are trying to avoid having to provide assistance (ie, extra ground staff etc) upon departure and arrival. Throw in a requirement to buy an extra ticket here & there and hey presto! A bit of money is clawed back to offset those darned fuel costs. That seems abundantly clear from the media statements made so far. OH&S is a convenient fall-guy (actually, probably more correctly, a variation on a straw-man argument. The wheelchair pax are the fall-guys).