The idea was to allow a sorta "RP-mode" for instances(Be it 5-mans or raids), where you could get as many people in you wished until a certain limit(40, as in an entire raid?) for events, no matter the levels(Though I suppose the raid leader should at least be of appropriate level). The instance would then either be chosen as completely empty, perhaps except for friendly NPCs, or filled with NPCs who give no exp and drop no loot. Those who are inside are then free to RP as of their choice.
Have a good day and give me some thoughts, criticism or whatever.