QBE aren't increasing the passenger limit, that was done by the Australian Government when they increased the limit under the Civil Aviation Carriers Liability Act. AOC holders have a legal obligation under the Act to have appropriate insurance in place to continue to excercise their privileges under their AOC for charter or RPT operations. The insurnce companies are now carrying a higher automatic liability limit on behalf of the AOC holder.
I would imagine that the other insurance companies will probaly do the same and adjust their premiums accordingly.